Threshold Stasis 3 Amplifier Capacitor Replacement

[Audioman12]

Hi hope can get an answer to these questions😋🤔🤔

I have a Threshold Stasis 3 with low temperature operation

I want to replace the Trim Pots as they are faulty

I will have to open the amp and do some stripping of parts and boards

Should I replace any of the caps while I have the unit open ?

I see some tantalum caps and some electrolytic ones too

According to the schematic it has the following caps per channel

1 of 4.7uf 25v
2 of 47uf 50v Radial type
1 of 470uf 6.3v Axial type
2 of 0.15uf 50v
1 of 0.1uf 400v
2 of 39pf
1 of 390pf
2 of 680pf

Which to replace ?

Thanking you in advance for the replies🤗🤗🤗

 

[rayma]

Which to replace ?

Yes, replace all of the electrolytic and tantalum types, but substitute electrolytics for the tantalums.
Use higher voltage ratings on all the new caps, if possible. I would leave the film and ceramic caps as-is.

 

[Audioman12]

A bit of confusion, clarity sought

Hi

Set about the task but found this point that does not make sense.

I see what I think is a capacitor here with the following written on it

PSll .001 +|-2% 100vdc

I would presume this is a capacitor of 0.001uf 100vdc with 2%tolerence

This value of capacitor however does not show on the circuit diagram

Am I wrong in this in some way

Please help

Thank you
Umesh

 

[Zen Mod]

that's solid cap 1nF/100Vdc , no need for replacing it

 

[rayma]

I would presume this is a capacitor of 0.001uf 100vdc with 2%tolerence.
This value of capacitor however does not show on the circuit diagram

Looks like that value was substituted for the two 680pF caps.

 

[Nelson Pass]

Yes

 

[Audioman12]

I have read that the original 47uf 50v Infstrument Devices caps are marked on the positive side and not the negative. Capacitors are usually marked on the negative.

So is it true then that these in the Threshold Stasis 3 are marked on the positive side ?

I have read this on this forum some time ago

Your help is appreciated

 

[Zen Mod]

picture ?

 

[Nelson Pass]

Yes, they have white arrows pointing toward the positive.

 

[Audioman12]

Those pics

Not great pics as I have not taken them out yet

These are the two radial 47uf 50v Instrument Devices capacitors

 

[Zen Mod]

who cares for stripes
just decipher how to put them - from schematic

 

[Audioman12]

Thank you for clearing up the info. Would have definitely messed it up without this vital info. Would have just gone on convention.

who cares for stripes
just decipher how to put them - from schematic

That would be the best way but just to be sure had to ask

I have one Threshold Stasis 3 with a blown channel due to ignorance so just being cautious

 

[Audioman12]

I don't believe that I have to consult the great oracle again.

Capacitors arrived today. ( sent a friend to buy them in major city close by )

They are the correct value but much longer.

Question of the day

Can I install away from the circuit board, sort of floating in one of the following configurations ?
Does this have any resonance or other detrimental implications ?
Please advise

 

[Zen Mod]

no problem

but I believe that drek (on picture) is ooooooold

can you post a picture to see everything written on them?

 

[Audioman12]

The writing on the cap is

Phillips 032 470uf 50v HP

Nothing else if that helps

 

[Zen Mod]

buy something newer

 

[Audioman12]

Hi

Did the cap swap out and switched on and a resistor blew. On the power transistor section T03 type .

Probably a transistor or two not sure. A question arises.

Does the axial cap in the picture also have an arrow pointing to the positive side as well ? As I presumed the axial cap would be conventionally noted

Anyway I will probably resort to professional services after this as I have had no luck with this amp. I now have two blown amps.

Should have probably asked this before switching on.

Hind sight 20/20

Please advise on this situation.

Thank you

 

[Zen Mod]

well , if you have difficulties correlating schematic with actual part position/orientation on pcb , then is really best to resort for professional service

in the end , it'll be faster and less expensive

 

[llwhtt]

The end with the rubber plug is "usually" always positive.

Craig

 

[Audioman12]

I replaced the trim pots as well.

When replacing the trim pots does one place the resistance between the two active legs on a high or low valve to protect the circuit down the line ?


The answer is probably obvious and scary coming from someone who is actually dabbling with electrical work