Re: VAX 4000 PSU (H7874) Schematics
I have one or two mostly new 4000 supplies here, plus two working 4000's. Did not know until recently this was an issue, I guess I have been lucky. b On Fri, Jun 8, 2018 at 9:04 AM, Holm Tiffe via cctalk wrote: > Aaron Jackson via cctalk wrote: > > > > On Thu, 7 Jun 2018, Aaron Jackson wrote: > > >> The VAX turns on and the status LED stays on F. The DC lamp does not > > >> illuminate on the PSU. 5V rail appears fine but there is nothing from > > >> the 12V rail. There were some *very* dodgy looking caps which I have > > >> replaced, and some *very* exploded MOSFETs, which I have also > > >> replaced. > > > > > > If that's all that you replaced, no wonder it still doesn't work ;-) > > > Usually shorted power transistors in SMPSUs also break one or more > fusable > > > resistors, maybe some diodes, maybe the driver IC or transistors. > > > So if you have anything that "exploded" in the power supply, be sure > there > > > is more work to be invested that replacing the obious parts. > > > > > > Christian > > > > Haha, okay, seems reasonable. I'll have to probe about a lot more > > then. Not giving up quite yet, even though everything I have read about > > this power supply has said that it is difficult to repair. So far, I > > would agree with such a statement. > > > > Thanks, > > Aaron. > > Difficult to repair? Probably since it is the worst switching PSU Desing > I ever meet, at least from seriveability and the mechanical point of view. > > I own an 4000/300 with an working again PSU (after some capacitor > changes) and I habe an PSU from a friend here..its works sometimes, > mostly not. > > Regards, > > Holm > > -- > Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, > Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583 > i...@tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741 > >
Looking for an ex-Sun employee; Alan Charlesworth
Hey all; I'd love to talk to Alan Charlesworth, who used to work for Sun and (I believe) CRS before that. I'm interested in his perspective on some historical happenings and Sun design work. If anyone knows him and might be willing to get me in contact with him I'd very much appreciate it. Unfortunately while I can find several papers he's written they all provide his Sun address, and there are three other prominent Alan Charlesworths that are making searching for him difficult. My thanks for your help; - JP
Re: VAX 4000 PSU (H7874) Schematics
Aaron Jackson via cctalk wrote: > > On Thu, 7 Jun 2018, Aaron Jackson wrote: > >> The VAX turns on and the status LED stays on F. The DC lamp does not > >> illuminate on the PSU. 5V rail appears fine but there is nothing from > >> the 12V rail. There were some *very* dodgy looking caps which I have > >> replaced, and some *very* exploded MOSFETs, which I have also > >> replaced. > > > > If that's all that you replaced, no wonder it still doesn't work ;-) > > Usually shorted power transistors in SMPSUs also break one or more fusable > > resistors, maybe some diodes, maybe the driver IC or transistors. > > So if you have anything that "exploded" in the power supply, be sure there > > is more work to be invested that replacing the obious parts. > > > > Christian > > Haha, okay, seems reasonable. I'll have to probe about a lot more > then. Not giving up quite yet, even though everything I have read about > this power supply has said that it is difficult to repair. So far, I > would agree with such a statement. > > Thanks, > Aaron. Difficult to repair? Probably since it is the worst switching PSU Desing I ever meet, at least from seriveability and the mechanical point of view. I own an 4000/300 with an working again PSU (after some capacitor changes) and I habe an PSU from a friend here..its works sometimes, mostly not. Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583 i...@tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
Re: VAX 4000 PSU (H7874) Schematics
Thanks Bill. I emailed him, some decent advice but mostly prices :) Aaron Bill Degnan writes: > There is a guy named at Joel from global-itcorp.com who has experience with > these, he may have an idea. Tell him you spoke with Bill Degnan. > b > > On Thu, Jun 7, 2018 at 3:49 PM, Aaron Jackson via cctalk < > cctalk@classiccmp.org> wrote: > >> I am trying to repair a VAX 4000 power supply. Does anyone have the >> schematics? I can't find anything on BitSavers and I'm not completely >> convinced it was even designed by DEC. >> >> The VAX turns on and the status LED stays on F. The DC lamp does not >> illuminate on the PSU. 5V rail appears fine but there is nothing from >> the 12V rail. There were some *very* dodgy looking caps which I have >> replaced, and some *very* exploded MOSFETs, which I have also >> replaced. >> >> If anyone has schematics, or know where I might find them, it would be >> much appreciated. >> >> Thanks, >> Aaron. >> >> -- Aaron Jackson PhD Student, Computer Vision Laboratory, Uni of Nottingham http://aaronsplace.co.uk
Re: VAX 4000 PSU (H7874) Schematics
> On Thu, 7 Jun 2018, Aaron Jackson wrote: >> The VAX turns on and the status LED stays on F. The DC lamp does not >> illuminate on the PSU. 5V rail appears fine but there is nothing from >> the 12V rail. There were some *very* dodgy looking caps which I have >> replaced, and some *very* exploded MOSFETs, which I have also >> replaced. > > If that's all that you replaced, no wonder it still doesn't work ;-) > Usually shorted power transistors in SMPSUs also break one or more fusable > resistors, maybe some diodes, maybe the driver IC or transistors. > So if you have anything that "exploded" in the power supply, be sure there > is more work to be invested that replacing the obious parts. > > Christian Haha, okay, seems reasonable. I'll have to probe about a lot more then. Not giving up quite yet, even though everything I have read about this power supply has said that it is difficult to repair. So far, I would agree with such a statement. Thanks, Aaron.
New Listings for Sellam's Collection Sales
I, too, have emailed Sellam with no response. But, I guess I am adding to the "broad-based whine" Wow. Kurt. -- Forwarded message -- From: Sellam Ismail To: Randy Dawson Cc: "General Discussion: On-Topic and Off-Topic Posts" < cctalk@classiccmp.org> Bcc: Date: Wed, 6 Jun 2018 21:59:42 -0700 Subject: Re: New Listings for Sellam's Collection Sales Hi Randy. I have stuff that you can't find on eBay. And I am not offering the eBay experience. This is me, Sellam, you are dealing with. When I can find actual closing sales online (I need some place to start), I generally go on the lower end of the mean of the data I find. It's a collectors market, sometimes I'm high, sometimes I'm low, but I'm trying. Do you know how to assess the value of items as diverse as what I'm listing? I do, it's a lot of work. Come help out if you have the time, I'll trade you for stuff. The listed prices are what I'm asking, as stated. I'm always open to offers, as stated. I price fairly, to move it, and if something sits for a while, you have a good chance of negotiating a price more to your liking, if you ask, but know that I am willing to sit on some things. I invested a lot of time, effort, blood, sweat, tears and money into my collection over many years. I'd like to recoup some of it. All you have done is propounded a broad-based whine. if there's something that interests you but the price is not right, let me know. I'm making many sales and many deals, stuff is moving. Ask and ye may well receive. Just be reasonable. Sellam On Wed, Jun 6, 2018 at 7:57 PM, Randy Dawson wrote: > Inspired by ebay for all the items there that never sell for the asking > price. > > > C'mon Sellam, you want to get out, how about lowering the prices a bit to > move things along? > > > -- > *From:* cctalk on behalf of Ed Sharpe via > cctalk > *Sent:* Wednesday, June 6, 2018 7:50 PM > *To:* sellam.ism...@gmail.com; cctalk@classiccmp.org; > cctalk@classiccmp.org > *Subject:* Re: New Listings for Sellam's Collection Sales > > do the prices keep increasing? > > In a message dated 6/4/2018 10:02:53 PM US Mountain Standard Time, > cctalk@classiccmp.org writes: > > > Hi Folks. > > I've reorganized my sales listings into a Google Sheets set. The > introductory page is here: > > https://docs.google.com/spreadsheets/d/1I53wxarLHlNmlPVf_ > HJ5oMKuab4zrApI_hiX0pNmy48/edit#gid=0 > > Use the tabs on the bottom of the sheet to navigate to the various "rooms". > > New items have been added and are listed here: > > https://docs.google.com/spreadsheets/d/1I53wxarLHlNmlPVf_ > HJ5oMKuab4zrApI_hiX0pNmy48/edit#gid=949372371 > > New items are always added to the New Arrivals Niche, so that's the first > place you should check when you visit my virtual online warehouse. I will > post a message to this list and the VCFed forums whenever new items are > listed, which will occur more regularly. > > As always, please inquire directly to me via e-mail for the fastest > response. > > Thanks! > > Sellam >
Re: VAX 4000 PSU (H7874) Schematics
On Thu, 7 Jun 2018, Aaron Jackson wrote: The VAX turns on and the status LED stays on F. The DC lamp does not illuminate on the PSU. 5V rail appears fine but there is nothing from the 12V rail. There were some *very* dodgy looking caps which I have replaced, and some *very* exploded MOSFETs, which I have also replaced. If that's all that you replaced, no wonder it still doesn't work ;-) Usually shorted power transistors in SMPSUs also break one or more fusable resistors, maybe some diodes, maybe the driver IC or transistors. So if you have anything that "exploded" in the power supply, be sure there is more work to be invested that replacing the obious parts. Christian
