Volume pot for Trio KA2000

[andyuk71]

As far as ‘Fix my pot’ goes, I think you have disassembled the balance section. Even if you have totally destroyed the front section, you can recover the volume section at the rear. This would mean no balance control, but at least he unit would be running.

Semanon, I understand your explanation - I must confess this is not how I thought it was wired. I've attached a part of the schematic that details the connections to VR-1, the volume control pot, however, I am not able to interpret the schematic in any confident manner at this stage, but I thought each 'gang' was a duplicate pot, one controlling the left channel volume, the other the right?
In any case, if I'm unable to find a suitable replacement or have the original repaired, I still think your suggestion works by using just the rear gang, providing that it's wired correctly.
Finally, I am going to take your advice and create a 'fix my pot' thread to see how vialble an option that is

 

[andyuk71]

Search Kenwood instead of Trio. I believe they are identical, except badging.

Wait a minute...I'm thinking Andyuk might mean that you are in the UK. Figured that out all by myself, I did.

Lol, yes i'm in the UK - you could be confident in guessing my age too

 

[Semanon]

I looked at the schematic and the service manual. This unit does not have separate balance controls. The volume control is split into two separately controllable pots. I’m a little dense this weekend, it seems.

I think a dual concentric 2-gang pot will be most difficult to find. Unless you can find a donor unit or can fix the existing one, a typical, easy-to-find pot will be fine. You will lose separate channel balance and loudness. However, it will work until a proper pot turns up.

 

[andyuk71]

I looked at the schematic and the service manual. This unit does not have separate balance controls. The volume control is split into two separately controllable pots. I’m a little dense this weekend, it seems.

I think a dual concentric 2-gang pot will be most difficult to find. Unless you can find a donor unit or can fix the existing one, a typical, easy-to-find pot will be fine. You will lose separate channel balance and loudness. However, it will work until a proper pot turns up.

I think a single 50k pot with a loudness tap would be fine too if they’re available- I quite like the loud option.

 

[JoseHH]

There are dual gang single shaft 50 K pots with loudness tap from Alpha Taiwan. They are reasonable in quality but they are smaller in size.
They may be available in your location.
If the tracks and wipers in your pot are not damaged you may be able to rebuild yours.
If the tracks are bad you may be able to fit wafers from other Alps potentiometers. It is possible to stil find NOS Alps 50K potentiometers with loudness tap. (I have recently seen some single gang 50K with tap in a local shop here in Bangkok -which admittedly is not so useful-, but ilustrates my point.) The ones with dual shaft are not easy to find.

 

[andyuk71]

Thank you Jose, this is very interesting and gives me more avenues to follow up. As the bottom pot is still useable, I have been considering just using that to control both channels, so this is my fall back option if nothing else is viable. I’ll have a look at the Alpha Taiwan stuff and see what’s available. Will let you know how I get on

 

[JoseHH]

, I have been considering just using that to control both channels, so this is my fall back option if nothing else is viable.

That will not work because it will mix the left and right channels and you w
ill loose the stereo imaging.
You need two separate tracks or gangs in your volume/balance control.
What i saw in your picture is that you lost the connection tab but the track is intact. Is this right?
Can you post a close up picture of the damaged wafer. I would like to see what was damaged.

 

[JoseHH]

This is the alpha potentiometer. It has the loudness tap at 25k approximately.
EDIT:
I believe that you need the "A" curve. This is a "B" type. They make both types one is linear and the other is logarithmic ( logarithmic is the one typically used for Volume potentiometers)

 

[andyuk71]

Hi Jose.
I can't say how much I appreciate your efforts in assiting me with this, you are very kind.
I understand your explanation of how using one pot for both channels won't work - I hadn't thought of this, thanks.
I'll take a better picture of the pot and upload shortly.
Do you think you could direct message me with a link to the Alpha pots? I understand that sending links on the message board is not allowed and I have previously fallen foul of this rule. If direct messaging links is also not allowed, then please don't do this either
I'll be back shortly with those photos.

 

[andyuk71]

Hi Jose, here's some more pics.

 

[JoseHH]

It looks like the carbon track has lots of scratches, as it was sanded. If this is the case, that track is unusable. The Alpha potentiometers ike the one i showed are available in Bangkok, at some small local shops, but they do not sell online. Unfortunately I can not find it online, but I found this and this. I have no affiliation with these shops.
Alternatively, try to contact Tayda electronics and see if they can supply the A-type. Tayda is based in Bangkok and is an online shop (once again, I have no affiliation with them).

 

[andyuk71]

Thanks for these efforts Jose. The pot on the Shopee site looks pretty perfect - just need to work out how to set up my account for international shipping; struggling to do this on first attempts...

 

[JoseHH]

If all this fails PM me. And I will see if I can help since my wife is Thai. While I am in Bangkok I can help.

 

[andyuk71]

Thanks Jose. Will PM you to let you know how I get on