- Peavey XRD680TB - 1 Update
- Do these 'lytics need to be replaced? - 7 Updates
- Oldtimer question (valves/tubes) - 6 Updates
| Darryl Widman <f6ceedb9c75b52f7fcc0a55cf0cfbf5d_1136@example.com>: May 14 11:37PM Unit came in completely dead. Read that others had to replace all output transistors, driver transistors and bias diodes. Other cures? -- |
| Cursitor Doom <curd@notformail.com>: May 14 05:05PM > My guess is that they have gotten very hot, one or more times. Which > would explain both the shrinkage of the covering and the bulge. The shrinkage looks pretty mild to me. I've seen caps that got so hot (heat and electrolytics don't go together well) that the plastic casing had formed puckered-up 'crowns' on top. All the caps I found in that state have turned out to be fucked, basically. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
| Bob Engelhardt <BobEngelhardt@comcast.net>: May 14 12:36PM -0400 On 5/14/2019 9:54 AM, Bob Engelhardt wrote: > https://imgur.com/GymXlUb > Thanks, > Bob Thanks for all the prompt and helpful replies. This is my step son's amp and I have decided that I'm not going to do any repair that might not be perfect in his eyes. So I'm going to return it and let him know that the caps should be replaced. |
| three_jeeps <jjhudak@gmail.com>: May 14 01:29PM -0700 On Tuesday, May 14, 2019 at 12:36:34 PM UTC-4, Bob Engelhardt wrote: > This is my step son's amp and I have decided that I'm not going to do > any repair that might not be perfect in his eyes. So I'm going to > return it and let him know that the caps should be replaced. "not going to do any repair that might not be perfect in his eyes" Hmmm strange choice of words? How are you quantifying a 'perfect repair'? Would 'perfect' mean replacing all components that may have been degraded? hence these caps are the first step. Do you suspect others? Carbon resistors change resistance with age...going to replace all of them? How old is the amp? Is it experiencing any other abnormalities? J |
| John Robertson <spam@flippers.com>: May 14 01:52PM -0700 On 2019/05/14 1:29 p.m., three_jeeps wrote: > Would 'perfect' mean replacing all components that may have been degraded? hence these caps are the first step. Do you suspect others? Carbon resistors change resistance with age...going to replace all of them? > How old is the amp? Is it experiencing any other abnormalities? > J This might be the level of restoration where you hollow out the old part and put the new part inside and then seal it back up... early vintage (1920s) radio collectors enjoy doing that! John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| whit3rd <whit3rd@gmail.com>: May 14 01:58PM -0700 On Tuesday, May 14, 2019 at 6:55:17 AM UTC-7, Bob Engelhardt wrote: > Are these "bulging"? How much bulge is too much? Or is _any_ bulging > to much? "If you can see that it's not flat, it's too much"? > https://imgur.com/GymXlUb That doesn't look like a problem at all. The "X" dents in the top of the capacitor are a pressure-relief scheme, intended to rupture if steam forms inside the capacitor, and there's no sign those are under stress. A must-replace scenario is when the "X" has ruptured and fluid is seen leaking, or (sometimes) the rubber seal on the other end of the capacitor has failed, which sometimes lifts the entire aluminum shell. A significant bulge but NO leaking means that there has been some overheating, which can mean a rectifier has shorted and the capacitor is not the main problem. Many low-ESR capacitor failures have occurred in recent decades, but these look like general-purpose capacitors, not known for high failure rates. If they are forty years old, replacement might be a good idea regardless. |
| tabbypurr@gmail.com: May 14 03:07PM -0700 On Tuesday, 14 May 2019 14:55:17 UTC+1, Bob Engelhardt wrote: > https://imgur.com/GymXlUb > Thanks, > Bob The best answer is to test them for C & ESR. Or replace, bulging caps are usually bad. NT |
| Bob Engelhardt <BobEngelhardt@comcast.net>: May 14 06:25PM -0400 On 5/14/2019 4:29 PM, three_jeeps wrote: >> return it and let him know that the caps should be replaced. > "not going to do any repair that might not be perfect in his eyes" > Hmmm strange choice of words? How are you quantifying a 'perfect repair'? ... The key part is the "in his eyes". I don't want to do work that _he_ might not find perfect. It's really annoying to do a favor and have it criticized. |
| Cursitor Doom <curd@notformail.com>: May 14 05:08PM On Tue, 14 May 2019 09:13:37 +1000, Clifford Heath wrote: >> What's worth salvaging from old photocopiers? I vaguely recall there's >> some exotic goodies in them somewhere. > Perhaps not exotic, but they tend to have a few nice 24V motors. I was trying to remember what exactly it was last night. I *think* there's a EHT generator in there to attract the 'soot' to the paper that can be easily converted into a 60kV taser. But I might easily be mistaken, so don't quote me on that. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
| Cursitor Doom <curd@notformail.com>: May 14 05:10PM On Tue, 14 May 2019 17:26:55 +0100, Mike Coon wrote: > Bletchley Park for several years, hopefully supporting their old > computer resusitation projects. > Mike. I really must get around to visiting that place some time. I've heard very good reports of it. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
| Mike Coon <gravity@mjcoon.plus.com>: May 14 05:26PM +0100 In article <qbcafc$6ea$1@dont-email.me>, curd@notformail.com says... > > See https://www.radiomuseum.org/r/taylor_valve_tester_47a47.html > Very nice, that. You should hang on to it; valves seem to be making a > comeback in some areas. Too late; assuming they have not thrown it away, it has been at Bletchley Park for several years, hopefully supporting their old computer resusitation projects. Mike. |
| three_jeeps <jjhudak@gmail.com>: May 14 01:46PM -0700 On Monday, May 13, 2019 at 11:50:31 AM UTC-4, Cursitor Doom wrote: > On Mon, 13 May 2019 09:39:11 -0500, Fox's Mercantile wrote: > > <http://www.junkbox.com/electronics/lowvoltagetubes.shtml> > Thanks! It's a shame that mostly all the links in the project section point to sites that are gone.... |
| three_jeeps <jjhudak@gmail.com>: May 14 01:49PM -0700 On Monday, May 13, 2019 at 7:13:40 PM UTC-4, Clifford Heath wrote: > > What's worth salvaging from old photocopiers? I vaguely recall there's > > some exotic goodies in them somewhere. > Perhaps not exotic, but they tend to have a few nice 24V motors. yes, motors, drive pullies, belts, lead screws, stepper motors, microswitches, |
| John Robertson <spam@flippers.com>: May 14 01:53PM -0700 On 2019/05/14 1:46 p.m., three_jeeps wrote: >>> <http://www.junkbox.com/electronics/lowvoltagetubes.shtml> >> Thanks! > It's a shame that mostly all the links in the project section point to sites that are gone.... http://web.archive.org John ;-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
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