I did not replace any of the other caps at that time, although with the age of these radios it probably would not be a bad idea. The thing with the cap on the PS board is that it can cause some strange things to happen when it starts to fail, which can include unintentional out-of-band emissions.
I recommend that you use caps rated for 105C temperature. Not because it gets that hot in there, but rather that they are more robust devices and should in theory last longer. 73 -Jim NU0C On Wed, 5 Mar 2014 22:25:03 +0000, Lehman, Rex wrote: >Hi Jim >Seen this post on replacing the 220 UF cap on PS bd for the DC to DC converter >and seen your older messages where you said you recap your TR-7. >Did you just recap the PS board or did you replace every electrolytic cap in >the TR-7. >Just curious as I have one of mine apart and did the PS bd thinking maybe its >worth it to do all of them. >Thanks >WB8TDG >Rex Lehman >Office +1.937.490.4474 >rex.leh...@meas-spec.com > > >-----Original Message----- >From: Drakelist [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Jim >Shorney >Sent: Monday, March 03, 2014 11:34 PM >To: drakelist@zerobeat.net; Mark Nace >Subject: Re: [Drakelist] TR7 - CW and ALC level > > >ALL of the screws for the card cage cover need to be there, and snug. Don't >overtighten, they will strip the chassis. > >The +10V and the frequency alignments are the most critical. You probably >won't need to touch the RF/IF cans or anything underneath the DR-7 except >maybe the carrier balance. The RIT center pot should be accessible from the >bottom through a hole in the parent board. > >Replace the filter capacitor on the DC-DC converter ("power supply") board. >Don't ask why, just do it. It is worthwhile to replace the fixed passband pots >and the +10 pot with 10-turn trimpots as long as you are at it. Unless you >have doubts about the calibration, I wouldn't touch the wattmeter and SWR >balance adjustments. Judgement call... > >AGC alignment should go by the book. If you will be doing CW, give Floyd's >article a read. It's spot on: > >http://www.wb4hfn.com/DRAKE/DrakeArticles/TR7_Key_Clicks.pdf > >There are some quick and dirty tech notes from Drake's service department here: > >http://www.zerobeat.net/drakelist/tr7bookalign.html > >If you have any questions, ask. > >73 > >-Jim >NU0C > >On Mon, 3 Mar 2014 19:36:27 -0800 (PST), Mark Nace wrote: > >>I bought my "new" TR7 28 years ago (as my first rig ever) and am about to do >>do my first alignment check. I have re-seated the boards once, and that cured >>most of the ills. I have a late-model TR7, along with the maint manual. If I >>do it "by the book", is there anything I should watch out for ?? > >Mark >N5KAE > > >-- >The universe we're in will reach absolute zero in three hours. Safe is >relative. - Idris, "The Doctor's Wife" > > > >_______________________________________________ >Drakelist mailing list >Drakelist@zerobeat.net >http://mailman.zerobeat.net/mailman/listinfo/drakelist -- Theres something out of place lets go and poke it with a stick. The Doctor, "Amys Choice" _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
