Re: H960 blank panel clips
From: Pete Turnbull: Tuesday, July 28, 2015 10:58 AM On 28/07/2015 18:22, Vincent Slyngstad wrote: What do folks think of the idea of thickening the shaft, terminating it in a hemisphere, but then cutting half-way down the result with a Y or X shaped cut? The cut would hopefully allow the result to flex and taper into the socket, providing plenty of grip without actually tearing anything up. Just a slit would do, and be much easier to incorporate in a moulded or machined item. I've placed a new design at: http://svn.so-much-stuff.com/svn/trunk/3D/rack-bracket/bracket-new.jpg http://svn.so-much-stuff.com/svn/trunk/3D/rack-bracket/bracket-new.stl http://svn.so-much-stuff.com/svn/trunk/3D/rack-bracket/bracket-new.skp The .stl file is in inches, so remember to scale it if you are planning to 3D print it! For those just following along, the .jpg will be the most useful. The SketchUp file is also provided, but unless you're a SketchUp user like me, that's actually of little use. (Do not attempt to cut into the spherical sections unless you've done that sort of thing in SketchUp before -- it's very hard to get it right.) I don't know if the design will work -- will the slit will provide enough flexibility, will the post crack, etc. Vince
Re: H960 blank panel clips
my take on these would be make them out of soft metal,(Al) thread the post holes and use a threaded post with a recess for either a "O" ring or tubing to hold the panel. - Jerry On Tuesday, July 28, 2015 7:47 PM, "ste...@malikoff.com" wrote: I think there are other ways to produce this than a one-piece molding, if the aforementioned RC balljoints aren't suitable replacements. I'd take some nylon, acetal, HDPE etc. threaded bar stock (plenty on eBay) and make a form tool for the ball and post combined, then knock them out on a lathe. Tap the block for the thread. The most time-consuming part in this would be the form tool profiling, but being soft material you could get away without the need of grinding a HSS toolbit. I've got some nylon bolts and my trusty Unimat lathe so I may give it a go to see if it works. Steve. Original Message Subject: Re: H960 blank panel clips From: "Chuck Guzis" Date: Wed, July 29, 2015 7:30 am To: gene...@classiccmp.org "On-Topic and Off-Topic Posts" -- > On 07/28/2015 01:01 PM, Noel Chiappa wrote: >> > From: Chuck Guzis >> >> > Does anyone have a photo or mechanical drawing of one of these things? >> >> There are several kinds. These: >> >> http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg >> > > The balls remind me of rod-end linkage stuff (this for the RC hobbyists): > > http://www.amain.com/rc-helicopters/sab-m2-steel-ball-linkage-5-sabh0538-s/p427854?gclid=CNLUkYLh_sYCFY9gfgodR-APCQ > > But I don't have any idea of size. But a good engineering findings > catalog might turn up something closer. > > --Chuck > >
RE: Microsoft multiuser Basic for the Altair 8800
Hi Jay, I appreciate you explaining reforming in such detail and I will look it up as you suggest and I'll definitely keep this in mind when I start checking things out in my Altair. Thank you very much. Kip Koon computer...@sc.rr.com http://www.cocopedia.com/wiki/index.php/Kip_Koon > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jay jaeger > Sent: Tuesday, July 28, 2015 11:01 PM > To: General Discussion: On-Topic and Off-Topic Posts > Subject: RE: Microsoft multiuser Basic for the Altair 8800 > > OK at the risk of restarting a long discussion about the value of reforming > or lack thereof > > Reforming a cap means to apply power to the cap at or a little below its > rated voltage but limiting the current with a resistor in series > with the cap until the voltage drop across the resistor indicates acceptably > low leakage current. At the low voltages in use on an Altair > I typically use something in the range of 4.7k ohms. I have a dual 1-20v > power supply to do this. > > The idea is that this redeposits some of the aluminum that had migrated into > the electrolyte while the cap was idle reducing the > leakage current of the capacitor. > > This procedure done correctly with the correct polariy and voltage will > never harm the cap, so it isn't unreasonable to reform all of > the filter caps on a linear supply like that on an Altair 8800. The current > list!meeting resistor prevents the cap frm drawing too much > current and overheating or worse until the reforming is complete or too much > time has elapsed without reaching an acceptably low > leakage current. > > Just google it and you will find articles on the procedures. > > As others have pointed out, this will not help if the cap has unacceptably > large effective series resistance (ESR). On a linear supply, > That will show up as unacceptably high ripple ac on top of the DC the supply > is designed to provide. > > I would test the supply with at least SOME test Load before using it to > supply the machine. > > When I did this to my Altair a few years back I think rather than > disassembling the power supply to unsolder the caps I clipped one lead > of each one so that one lead was free, but that then leaves one with the need > to splice them back, but does avoid potential damage > to the board. I also recently did that with an ALTOS which has switching > supplies. Both would probably have done just fine without > reforming. I also did in on an IMSAI, same story. I also did it to a pdp12, > which had blown out rectifier before I did this. > > Doing a good job of restoring a machine does often mean disassembling and > reassembling. It comes with the territory. > > It sounds like you !might have pretty limited electronics experience, and if > that is the case you might try and find Someone local to > help you over the humps. > > SAFETY FIRST. > > > Kip Koon wrote: > > >Hi Jay, > >Thank you so much for the advice. What is reforming a capacitor? Does that > >mention the electrolytic capacitors may have to be > repolarized? If so, how to you do that? How do you know if a power cap > needs to be reformed or not? To get to the transformer, I'll > have to take out just about everything including the card guides. Labeling > the wires will be paramount too. I don't want to get those > rascals mixed up! If remember my linear power supplies correctly, I don't > need to put a load on them when I test them, but I will need > to test the caps disconnected, correct? I doesn't sound too difficult, just > tedious and much detail to consider. I definitely want to > baby this thing. :) Thanks again for the restoration advice. I'll need it > and more before I'm finished. Take care my friend. > > > >Kip Koon > >computer...@sc.rr.com > >http://www.cocopedia.com/wiki/index.php/Kip_Koon > > > > > >> -Original Message- > >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jay > >> Jaeger > >> Sent: Thursday, July 16, 2015 9:39 AM > >> To: cctalk@classiccmp.org > >> Subject: Re: Microsoft multiuser Basic for the Altair 8800 > >> > >> First of all, safety first when working around these power supplies. > >> You have mains voltage exposed all over the place, including the front > >> panel switch. > >> > >> What I typically do is take it all the boards out and disconnect the > >> power supply, and pull it out. I then re-form the capacitors by > >> taking them off completely or, more often, unsoldering one lead. In > >> one case recently the power supply was regulated (an Altos computer), > >> and the power transistors were inserted through the power supply case > >> and into the board from the backside, making removal both a pain and > >> a little risky, so I just clipped one lead of each larger in place to do > >> the re-forming (it turned out that in that particular case, they > really didn't need it). I'd be pretty surprised if you
RE: Microsoft multiuser Basic for the Altair 8800
OK at the risk of restarting a long discussion about the value of reforming or lack thereof Reforming a cap means to apply power to the cap at or a little below its rated voltage but limiting the current with a resistor in series with the cap until the voltage drop across the resistor indicates acceptably low leakage current. At the low voltages in use on an Altair I typically use something in the range of 4.7k ohms. I have a dual 1-20v power supply to do this. The idea is that this redeposits some of the aluminum that had migrated into the electrolyte while the cap was idle reducing the leakage current of the capacitor. This procedure done correctly with the correct polariy and voltage will never harm the cap, so it isn't unreasonable to reform all of the filter caps on a linear supply like that on an Altair 8800. The current list!meeting resistor prevents the cap frm drawing too much current and overheating or worse until the reforming is complete or too much time has elapsed without reaching an acceptably low leakage current. Just google it and you will find articles on the procedures. As others have pointed out, this will not help if the cap has unacceptably large effective series resistance (ESR). On a linear supply, That will show up as unacceptably high ripple ac on top of the DC the supply is designed to provide. I would test the supply with at least SOME test Load before using it to supply the machine. When I did this to my Altair a few years back I think rather than disassembling the power supply to unsolder the caps I clipped one lead of each one so that one lead was free, but that then leaves one with the need to splice them back, but does avoid potential damage to the board. I also recently did that with an ALTOS which has switching supplies. Both would probably have done just fine without reforming. I also did in on an IMSAI, same story. I also did it to a pdp12, which had blown out rectifier before I did this. Doing a good job of restoring a machine does often mean disassembling and reassembling. It comes with the territory. It sounds like you !might have pretty limited electronics experience, and if that is the case you might try and find Someone local to help you over the humps. SAFETY FIRST. Kip Koon wrote: >Hi Jay, >Thank you so much for the advice. What is reforming a capacitor? Does that >mention the electrolytic capacitors may have to be repolarized? If so, how to >you do that? How do you know if a power cap needs to be reformed or not? To >get to the transformer, I'll have to take out just about everything including >the card guides. Labeling the wires will be paramount too. I don't want to >get those rascals mixed up! If remember my linear power supplies correctly, I >don't need to put a load on them when I test them, but I will need to test the >caps disconnected, correct? I doesn't sound too difficult, just tedious and >much detail to consider. I definitely want to baby this thing. :) Thanks >again for the restoration advice. I'll need it and more before I'm finished. >Take care my friend. > >Kip Koon >computer...@sc.rr.com >http://www.cocopedia.com/wiki/index.php/Kip_Koon > > >> -Original Message- >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jay Jaeger >> Sent: Thursday, July 16, 2015 9:39 AM >> To: cctalk@classiccmp.org >> Subject: Re: Microsoft multiuser Basic for the Altair 8800 >> >> First of all, safety first when working around these power supplies. >> You have mains voltage exposed all over the place, including the front panel >> switch. >> >> What I typically do is take it all the boards out and disconnect the power >> supply, and pull it out. I then re-form the capacitors by >> taking them off completely or, more often, unsoldering one lead. In one >> case recently the power supply was regulated (an Altos >> computer), and the power transistors were inserted through the power supply >> case and into the board from the backside, making >> removal both a pain and a little risky, so I just clipped one lead of each >> larger in place to do the re-forming (it turned out that in that >> particular case, they really didn't need it). I'd be pretty surprised if >> you actually had to replace your capacitors. For reforming I have >> had pretty good luck with a 4.7K ohm resistor in serial with the capacitor, >> and in more than half the cases, the capacitors really didn't >> need it. >> >> The transformer is either good or not - and it is probably just fine. >> Just measure its output voltages. Do make sure that the transformer is >> wired for your voltage depending upon where you live. One >> could disconnect it first, but the odds of it putting out too high a voltage >> are very very slim, so long as it is wired for the mains voltage >> wherever you happen to live. Bad ones either put out nothing for one of the >> voltages (open winding) or get hot (short
Re: H960 blank panel clips
I think there are other ways to produce this than a one-piece molding, if the aforementioned RC balljoints aren't suitable replacements. I'd take some nylon, acetal, HDPE etc. threaded bar stock (plenty on eBay) and make a form tool for the ball and post combined, then knock them out on a lathe. Tap the block for the thread. The most time-consuming part in this would be the form tool profiling, but being soft material you could get away without the need of grinding a HSS toolbit. I've got some nylon bolts and my trusty Unimat lathe so I may give it a go to see if it works. Steve. Original Message Subject: Re: H960 blank panel clips From:"Chuck Guzis" Date:Wed, July 29, 2015 7:30 am To: gene...@classiccmp.org "On-Topic and Off-Topic Posts" -- > On 07/28/2015 01:01 PM, Noel Chiappa wrote: >> > From: Chuck Guzis >> >> > Does anyone have a photo or mechanical drawing of one of these things? >> >> There are several kinds. These: >> >>http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg >> > > The balls remind me of rod-end linkage stuff (this for the RC hobbyists): > > http://www.amain.com/rc-helicopters/sab-m2-steel-ball-linkage-5-sabh0538-s/p427854?gclid=CNLUkYLh_sYCFY9gfgodR-APCQ > > But I don't have any idea of size. But a good engineering findings > catalog might turn up something closer. > > --Chuck > >
Re: Equipment available (Wichita, Ks)
On 07/28/2015 12:34 PM, Shaun Halstead wrote: Still cleaning the shop, trying to be out by the end of the week-ish. We have the following equipment available: TU-80 family tape drive, in frame. Works, passes diagnostics. Make offer. Photos: http://microfilmks.com/LMSI/ Hmm, that's a CDC / Laser Magnetic Storage 92185 drive, right? Looks like it probably has the buffered Pertec interface, from the two connectors on the back. I've been looking for a 92185 with the SCSI interface (or just the SCSI interface board to plug into a generic 92185). (I have 2 working 92185s with the Pertec interface, and I kludged-up a board that will read my archival tapes, but it would be nice to have one that makes a more direct connection.) Jon
Re: H960 blank panel clips
> There are several kinds. ... I'll look and see if I have any of those, > to take a photo of. Alas, I don't. I do have some of the third kind (which are intermediate between those two previously discussed; they have the holes for bolting to the rack, but don't have the captive nuts). > From: William Donzelli > I THINK YOU FORGOT SOMETHING... I linked to the eBay listing in the first post in the thread. Anyway, the sale's over now? > toober Ah, so it's you I've been buying PDP-11 stuff from! I like the user name! :-) Noel
Re: DEC Power Conditioner on Ebay
On Tuesday (07/28/2015 at 11:22AM -0400), Douglas Taylor wrote: > I ran into this looking for something else on ebay: > > Digital Constant Voltage Conditioner H7225 item 331591861028 > > I don't think I ever saw one of these before, were they of any use? I have one. Heavy beast. It is a ferro-resonant transformer that is roughly equivalent to what folks may know as a "Sola" (now owned by Emerson) or other sort of line voltage stabilizer. Mine is model 7225-AA and is only rated at 4A @ 120VAC and for the weight, seems like I'm getting jipped. I don't know what DEC's intended use was for them but I have used mine at ham radio antenna range testing and other outdoor venues where the AC power comes from a generator or over a very long extension cord and have powered small amounts of test equipment or radio gear from it. It takes a wider range AC input and "regulates" it to 120V, with some amount of filtering and transient supression behavior. -- Chris Elmquist
Re: H960 blank panel clips
On 07/28/2015 01:01 PM, Noel Chiappa wrote: > From: Chuck Guzis > Does anyone have a photo or mechanical drawing of one of these things? There are several kinds. These: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg The balls remind me of rod-end linkage stuff (this for the RC hobbyists): http://www.amain.com/rc-helicopters/sab-m2-steel-ball-linkage-5-sabh0538-s/p427854?gclid=CNLUkYLh_sYCFY9gfgodR-APCQ But I don't have any idea of size. But a good engineering findings catalog might turn up something closer. --Chuck
Re: DC300XL/P-600 tapes available
On 07/28/2015 11:19 AM, Shaun Halstead wrote: > While cleaning up the shop, I found a stockpile (qty: 85) of brand new, in > the plastic wrap, > Carlisle DC300XL/P-600 QIC tapes. They're arranged in one complete case of > 50 (subdivided into > boxes of 10, each of which has two smaller boxes of 5). The boss wants > something for them, but > didn't say how much. I'm asking $0.50 per tape, in lots of 10. $20 for the > full case. You pay > shipping from Wichita, Ks 67213. > > --Shaun > To follow up on this, most of the tapes appear to have failed drive belts. The tapes with good belts have already been claimed. If anyone is interested in tapes with failed belts, drop me a note off-list. --Shaun
Re: H960 blank panel clips
On Tue, 28 Jul 2015, William Donzelli wrote: There are several kinds. These: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg You know...that wouldn't be terribly difficult to print. The heat-set inserts are easily obtainable too. (that little metal threaded bit) Anyone have a broken one they can send me for Evil Experiments? :) g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!
Re: H960 blank panel clips
> There are several kinds. These: > > http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg I THINK YOU FORGOT SOMETHING... -- toober
Re: H960 blank panel clips
> From: Chuck Guzis > Does anyone have a photo or mechanical drawing of one of these things? There are several kinds. These: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg are some of the better ones; they are connected to the rack via countersunk screws (go in the holes), and have embdedded nuts for use with the blank panels which have the matching captured bolts. The 'usual' ones don't have the embedded nuts, just the two ball/post things on the ends, and to attach them to the rack, they have (on the back) a pair of prongs with a fishhook-tang-like capture device on them. The back prongs were an even bigger crock than the ball-and-post things. The latter at least worked, even if they did occasionally break; the prongs wouldn't hold for s^*&^(*. I'll look and see if I have any of those, to take a photo of. Noel
Re: H960 blank panel clips
Does anyone have a photo or mechanical drawing of one of these things? You've got me curious now. --Chuck
Re: H960 blank panel clips
On 7/28/15 10:22 AM, Vincent Slyngstad wrote: What do folks think of the idea of thickening the shaft, terminating it in a hemisphere, but then cutting half-way down the result with a Y or X shaped cut? The cut would hopefully allow the result to flex and taper into the socket, providing plenty of grip without actually tearing anything up. Yes, the problem is there is no give in the plastic, along with the material itself being too inflexible even when it was new so the shaft should have been split. Whoever came up with it never thought about taking a panel off. There is no practical way to do that without bending the shafts.
Re: H960 blank panel clips
On 28/07/2015 18:22, Vincent Slyngstad wrote: What do folks think of the idea of thickening the shaft, terminating it in a hemisphere, but then cutting half-way down the result with a Y or X shaped cut? The cut would hopefully allow the result to flex and taper into the socket, providing plenty of grip without actually tearing anything up. Just a slit would do, and be much easier to incorporate in a moulded or machined item. -- Pete Pete Turnbull
Re: H960 blank panel clips
From: Charles Dickman: Tuesday, July 28, 2015 9:03 AM If the posts and balls are metal, the panel sockets are going to crack because there will not be any give in the shaft. If the ball and shaft is replaced with a solid pin, the panel sockets will get damaged because the socket will have to flex to conform to the pin. What he said :-). I like the idea of an X cut in the ball. What do folks think of the idea of thickening the shaft, terminating it in a hemisphere, but then cutting half-way down the result with a Y or X shaped cut? The cut would hopefully allow the result to flex and taper into the socket, providing plenty of grip without actually tearing anything up. Vince
Equipment available (Wichita, Ks)
Still cleaning the shop, trying to be out by the end of the week-ish. We have the following equipment available: TU-80 family tape drive, in frame. Works, passes diagnostics. Make offer. Photos: http://microfilmks.com/LMSI/ Unknown power supply module. Has NCR part numbers but google gives no love. +5 (x2), -5, +12, -12. Make offer. Photos: http://microfilmks.com/Ebay/UnknownPSU1.jpg and UnknownPSU2.jpg Discom electron tube, PN 123788-2. These came out of COM microfiche cameras, and have a blue display. Not sure how to go about shipping them securely, but if you're interested, we can figure it out. I have several of these. DEC SHD1Z-ZZ SCSI drive cabinet, tower configuration. Has SCSI-2 personality module, power supply, SCSI terminator and cable, 6 drive trays for 50-pin drives. Also has 4 spare drive trays and one spare power supply. Includes 6 1.2G SCSI drives, or if you prefer, I can remove them to lower the shipping weight. Asking $50 obo. All shipping is from Wichita, Ks, 67213 --Shaun
Re: H960 blank panel clips
On 28/07/2015 17:52, Tothwolf wrote: If they are made of ABS and the ball isn't critical, why not mill or drill out a small bit of the broken stem and solvent weld in some round ABS stock to make a new stem? Methylene chloride (dichloromethane) works extremely well for ABS (methyl ethyl ketone in my experience does not work very well with ABS). I think the ball size is fairly critical but the exact length of the shaft is less so. The problem is that the ball normally breaks off just where it joins the stem, and ends up stuck in the panel, so it has to be extracted first (I use a small drill followed by an easy-out). MEK is very commonly used for ABS here (industrially) and works fine for me. It's even pretty good at welding (gluing, in this case, really) ABS and PVC together (you need THF for PVC alone). And getting thin round ABS isn't always easy, though some model shops do carry it. I'd insert a bit of aluminium rod, myself, which makes it less likely to happen again. -- Pete Pete Turnbull
RE: Microsoft multiuser Basic for the Altair 8800
Hi Jay, Thank you so much for the advice. What is reforming a capacitor? Does that mention the electrolytic capacitors may have to be repolarized? If so, how to you do that? How do you know if a power cap needs to be reformed or not? To get to the transformer, I'll have to take out just about everything including the card guides. Labeling the wires will be paramount too. I don't want to get those rascals mixed up! If remember my linear power supplies correctly, I don't need to put a load on them when I test them, but I will need to test the caps disconnected, correct? I doesn't sound too difficult, just tedious and much detail to consider. I definitely want to baby this thing. :) Thanks again for the restoration advice. I'll need it and more before I'm finished. Take care my friend. Kip Koon computer...@sc.rr.com http://www.cocopedia.com/wiki/index.php/Kip_Koon > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jay Jaeger > Sent: Thursday, July 16, 2015 9:39 AM > To: cctalk@classiccmp.org > Subject: Re: Microsoft multiuser Basic for the Altair 8800 > > First of all, safety first when working around these power supplies. > You have mains voltage exposed all over the place, including the front panel > switch. > > What I typically do is take it all the boards out and disconnect the power > supply, and pull it out. I then re-form the capacitors by > taking them off completely or, more often, unsoldering one lead. In one case > recently the power supply was regulated (an Altos > computer), and the power transistors were inserted through the power supply > case and into the board from the backside, making > removal both a pain and a little risky, so I just clipped one lead of each > larger in place to do the re-forming (it turned out that in that > particular case, they really didn't need it). I'd be pretty surprised if you > actually had to replace your capacitors. For reforming I have > had pretty good luck with a 4.7K ohm resistor in serial with the capacitor, > and in more than half the cases, the capacitors really didn't > need it. > > The transformer is either good or not - and it is probably just fine. > Just measure its output voltages. Do make sure that the transformer is wired > for your voltage depending upon where you live. One > could disconnect it first, but the odds of it putting out too high a voltage > are very very slim, so long as it is wired for the mains voltage > wherever you happen to live. Bad ones either put out nothing for one of the > voltages (open winding) or get hot (shorted winding). > Neither is dangerous to the rest of the power supply. > > Then, check all the voltages to make sure they are not way too high, and > throw and oscilloscope on it to make sure that there isn't a > whole lot > of ripple (typically caused by a bad rectifier). Remember that on the > original Altair and most S100 machines each board had its own regulator, so > this isn't an exact thing. (On my machine, I actually had > to add a second 8V supply in order to provide power for a backplane > completely full of boards.) > > For bootstraps, perhaps look for a ROM board on eBay (a Bytesaver or the > like), and burn yourself a ROM. > > For a serial card, you can find T-UART or IMSAI MIO and the like show up > on eBay pretty frequently. Be patient so you don't overpay. ;) Real > MITS Altair cards come up far less frequently. Make sure you research (say, > on bitsavers.org/pdf) which ones support current loop if > you really want to hook up a real teletype. > > Not sure where you'd find your multi-user basic, but there is quite a lot of > Altair/S100 software available as part of the SimH > environment, and a separate web site at http://schorn.ch/altair_6.php > > JRJ > > On 7/15/2015 1:56 PM, Kip Koon wrote: > > Hi Drlegendre, > > How did you go about checking things out before you applied power for the > > first time (again)? :) I think I need to check out the > electrolytic capacitors and the transformer at least. > > In my system, the front panel is wired to the backplane along with the > > power supply wires so when I do power up, how do I protect > everything? > > There are screws the power wires come from, but they are difficult to get > > to. Do I need to consider replacing any other caps? > > Do you have a write up about your experience? Any help you can give in the > > hardware department is most appreciated. Thanks in > advance. Take care my friend. > > > > Kip Koon > > computer...@sc.rr.com > > http://www.cocopedia.com/wiki/index.php/Kip_Koon > > > > > > > >> -Original Message- > >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of > >> drlegendre . > >> Sent: Wednesday, July 15, 2015 1:15 AM > >> To: General Discussion: On-Topic and Off-Topic Posts > >> Subject: Re: Microsoft multiuser Basic for the Altair 8800 > >> > >> Hey Kip > >> > >> I can't help you with
Re: H960 blank panel clips
On Tue, 28 Jul 2015, Pete Turnbull wrote: On 27/07/2015 23:13, Tothwolf wrote: On Mon, 27 Jul 2015, John Wilson wrote: The only thing here is, it's a *terrible* design. Those damn nubs snap off so easily (I'm sure decades of outgassing haven't helped), even when you're expecting it and being super careful. Yes, even in the late 70s i recall them being considered fragile. Are the original parts made of nylon? If so, that might explain the tendency for them to break. Nylon 6/6 is hygroscopic, and over a long period of time, it could very well be swelling up just enough so the bulb portions are more likely to break off. No, they're ABS - at least mine are, I just tested a few. I don't know what grade, though, and perhaps something more flexible and forgiving - a different grade of ABS, semi-rigid PVC, or nylon would be better. My suggestion, however, would be to incorporate a vertical slit in the ball and a couple of millimeters of the stem, so they're a less tight and less critical fit. Might help, especially with a less brittle plastic. If they are made of ABS and the ball isn't critical, why not mill or drill out a small bit of the broken stem and solvent weld in some round ABS stock to make a new stem? Methylene chloride (dichloromethane) works extremely well for ABS (methyl ethyl ketone in my experience does not work very well with ABS). I've been using Plast-I-Weld (Flex-I-File) but in the past I've also used Tenax 7R and Proweld (Ambroid), however Tenax 7R and Proweld have both since been discontinued. Another option worth considering is polyacetal / polyoxymethylene (Delrin). It is tough, stable and inexpensive (but not as inexpensive as ABS). PVC cold flows under pressure and Nylon absorbs moisture and expands over time, so neither of those are all that great for this sort of application.
Re: H960 blank panel clips
From: quapla: Tuesday, July 28, 2015 2:22 AM @Vince Can you make a '.stp' or '.igs' file of the bracket as shown in the image 'bracket-screws.jpg' but with straight poles rather than the 'ball on a stick' version? I could widen the post to 1/4", so the result would be a post with a hemispherical top. I can't warrant that it won't be strong enough to crack the tapered tubes in the panels, though. Those are also aging, brittle plastic, but not nearly as easy to replace! However, I don't have the tooling to export in either '.stp' or '.igs', and it looks like the export plug-ins for that cost money. Maybe someone else has tools that can do that? Vince
Re: H960 blank panel clips
On Tue, Jul 28, 2015 at 11:29 AM, Pete Turnbull wrote: > > No, they're ABS - at least mine are, I just tested a few. I don't know what > grade, though, and perhaps something more flexible and forgiving - a > different grade of ABS, semi-rigid PVC, or nylon would be better. > > My suggestion, however, would be to incorporate a vertical slit in the ball > and a couple of millimeters of the stem, so they're a less tight and less > critical fit. Might help, especially with a less brittle plastic. I tend to think the design is actually pretty good IF the posts were more flexible and tougher. If the post flexes, it can accomodate slight misalignment without undo stress on the panel.The friction fit of the ball in the socket doesn't change with misalignment either. The method also doesn't require any clearance between adjacent panels since it comes straight off the pins. If the posts and balls are metal, the panel sockets are going to crack because there will not be any give in the shaft. If the ball and shaft is replaced with a solid pin, the panel sockets will get damaged because the socket will have to flex to conform to the pin. I like the idea of an X cut in the ball.
DC300XL/P-600 tapes available
While cleaning up the shop, I found a stockpile (qty: 85) of brand new, in the plastic wrap, Carlisle DC300XL/P-600 QIC tapes. They're arranged in one complete case of 50 (subdivided into boxes of 10, each of which has two smaller boxes of 5). The boss wants something for them, but didn't say how much. I'm asking $0.50 per tape, in lots of 10. $20 for the full case. You pay shipping from Wichita, Ks 67213. --Shaun
Re: H960 blank panel clips
On 28/07/2015 06:10, Arno Kletzander wrote: metal ball heads with a hex base on threaded posts are available as spares for R/C cars and similar Those are ball joints for servo arms, we use them on helicopters too. But ones I've seen are too small, and I don't think you'd get any with long enough stems and the right diameter ball. -- Pete Pete Turnbull
Re: H960 blank panel clips
On 27/07/2015 23:13, Tothwolf wrote: On Mon, 27 Jul 2015, John Wilson wrote: The only thing here is, it's a *terrible* design. Those damn nubs snap off so easily (I'm sure decades of outgassing haven't helped), even when you're expecting it and being super careful. Yes, even in the late 70s i recall them being considered fragile. Are the original parts made of nylon? If so, that might explain the tendency for them to break. Nylon 6/6 is hygroscopic, and over a long period of time, it could very well be swelling up just enough so the bulb portions are more likely to break off. No, they're ABS - at least mine are, I just tested a few. I don't know what grade, though, and perhaps something more flexible and forgiving - a different grade of ABS, semi-rigid PVC, or nylon would be better. My suggestion, however, would be to incorporate a vertical slit in the ball and a couple of millimeters of the stem, so they're a less tight and less critical fit. Might help, especially with a less brittle plastic. -- Pete Pete Turnbull
DEC Power Conditioner on Ebay
I ran into this looking for something else on ebay: Digital Constant Voltage Conditioner H7225 item 331591861028 I don't think I ever saw one of these before, were they of any use?
Re: H960 blank panel clips
On 2015-07-27 18:51, Vincent Slyngstad wrote: From: Noel Chiappa: Monday, July 27, 2015 8:58 AM Time to find someone who can do injection molding... (I don't think these could be 3D printed, the necks of the bulb-heads are under a lot of stress when removing panels, they often snap off; will 3D printed parts be that strong?) They are actually pretty straight-forward to cast, especially if you don't need the metal nut in the middle. I've made molds with RTV, then cast parts out of 2 part resin. The molds do wear out, where you pull the bulb-heads through. I've also had them 3D printed successfully, and if you're careful about the print direction, the bulb-heads are sufficiently strong in ABS. (I haven't tried it in PLA. Sintered nylon would also probably work, but would be expensive.) From: quapla: Monday, July 27, 2015 9:14 AM Maybe a future possibility to have a (maybe Chinese) manufacturer make a batch of 1000, 2000 or maybe 1 clips with a type of plastic which is slightly more flexible so that they do not break off to quickly? I like that they almost always break before the panel itself does, so don't make them too strong. I actually damaged a panel once by replacing the bulb-head with a screw (head). (Maybe should have used a nylon screw.) Also, there are several flavors. You can see a few toward the bottom of: http://www.so-much-stuff.com/pdp8/cad/3d.php though I don't have that exact flavor with the nut in the center. That makes ordering 1 a challenge, since what's actually needed is probably a mix of the various flavors. Vince Hmm, I have 3 versions, the ones with the nut, the ones without the nut and the one with the clamps which goes into the cabinet holes. I guess the ones without the nut and without the rack clamps may be the preferred ones, as there are always ways to bolt the panel clips to the rack posts. @Al Kossow Yes, straight pins would be better so less break off chances. @John Wilson Yes, local production is always better, but to keep it affordable for a group of private individuals, costs is usually more important. Regarding the base material, would ABS plastic the best solution? (Like the Lego bricks)? I did find a place in Belgium, who has their production facility in China. They offer up to 70% price reduction so it sounds interesting. (http://www.kunststof-spuitgieten.be, alas only in Dutch). @Vince Can you make a '.stp' or '.igs' file of the bracket as shown in the image 'bracket-screws.jpg' but with straight poles rather than the 'ball on a stick' version? I need one of these formats to ask them for a price offer based on the 1000 / 2000 / 1 batch size. Ed -- Dit is een HTML vrije email / This is an HTML free email. Zeg NEE tegen de 'slimme' meter.
