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andyrlb
23-05-2018, 09:56
Help ....please
Ok so I’m going to dive in BUT !!
I can’t identify the smaller blue caps and those bigger black ones are no longer available.
I have researched all the posts on other sites but they’re years old and I’ve had no reply from the person posting the thread.
It’s imperative that I don’t lose the magic .
I’m no expert at this but it doesn’t scare me either.
I will replace each component one at a time and listen in between each stage .
At some point someone has replaced the horrible original speaker terminals so I’m now wondering if this has been recapped (all the caps are bright and shiny )there is an orange gunk around the base of the caps which could have been left from the original caps ? Or is this wishful thinking [emoji848] https://uploads.tapatalk-cdn.com/20180523/3f6a83c5bef0952cdacfa25f16881e38.jpghttps://uploads.tapatalk-cdn.com/20180523/bdcb0deefdccd7c23e9862670d089239.jpghttps://uploads.tapatalk-cdn.com/20180523/138630516b4324ae5faeb027a62e5021.jpghttps://uploads.tapatalk-cdn.com/20180523/edc9df79aec111e406d21c028114134b.jpghttps://uploads.tapatalk-cdn.com/20180523/68b85b354baedfa3de17725bdeef342c.jpghttps://uploads.tapatalk-cdn.com/20180523/1d2f67f0486791fa876dbc3784862b66.jpg


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DiveDeepDog
23-05-2018, 10:03
Looks like its been done already to my untrained eyes.

If its working and sounds OK I'd be very tempted to leave it alone...
andyrlb
23-05-2018, 10:05
Looks like its been done already to my untrained eyes.

If its working and sounds OK I'd be very tempted to leave it alone...

That’s what I thought [emoji189] also I’ve now looked at the underside of the circuit board and the soldering is different around the larger black caps .
It’s going back together now


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walpurgis
23-05-2018, 10:08
I never re-cap anything unless it's ridiculously old or there's a suspect looking cap.
andyrlb
23-05-2018, 10:09
I never re-cap anything unless it's ridiculously old or there's a suspect looking cap.

Music to my ears [emoji16]


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andyrlb
23-05-2018, 11:28
What's access to the underside of the board like? If it's a pain in the backside I'd be tempted to leave it alone as much as possible. The flying leads are attached by "wire wrap", which was common with Japanese equipment of that era. It's actually a very good way to make a joint but impossible to remove and then re-wrap.
The usual "re-cap" involves replacing just the main power supply reservoir capacitors. If you want to go further you could replace all the electrolytics, though there are probably dozens of them.
I'm not sure about the orange gunk. Yes, it could be residue from the original caps which have since been replaced.

It’s all back together now and singing away , thanks for your input Andrew .


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Primalsea
23-05-2018, 13:17
I think the brown stuff is just the standard glue that the factory would have used to glue in the capacitors after soldering. This is normally done just to stop them moving. If you think you need to do this to the new replacement caps you can use a small tube of cheap silicone, putting 3 small blobs around the bottom. I doubt that it is really necessary.

Assuming that the replacement capacitors have the same voltage and capacitance ratings as the originals the only potential concern would be the ripple current ratings of the large PSU caps. Ripple currents might be relatively high when the amp runs in class A. The the caps don't have a high enough rating they could fail prematurely. I suspect you are OK as the amp is not really a powerhouse beast.
andyrlb
23-05-2018, 13:25
I think the brown stuff is just the standard glue that the factory would have used to glue in the capacitors after soldering. This is normally done just to stop them moving. If you think you need to do this to the new replacement caps you can use a small tube of cheap silicone, putting 3 small blobs around the bottom. I doubt that it is really necessary.

Assuming that the replacement capacitors have the same voltage and capacitance ratings as the originals the only potential concern would be the ripple current ratings of the large PSU caps. Ripple currents might be relatively high when the amp runs in class A. The the caps don't have a high enough rating they could fail prematurely. I suspect you are OK as the amp is not really a powerhouse beast.

Hi Paul, it’s all back together now .

Cheers


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snowman_al
23-05-2018, 13:56
Nice amp by the way, very sweet sound and I like the different style.

The black 6800uf caps are Panasonic TS-UP series. Sadly no longer in production, but excellent quality. As long as they are the 63v ones, the ripple is 4.6 amps at 100Hz, so fine. Pity they are not the 105 degree C ones though...

As said previously someone has recapped it and haven't bothered to clean the glue from the PWB too well. Cosmetics.