Teisco Checkmate 25 Solid State Low Signal

[g1]

Any reason to not post the schematic here?

I thought about that too. But since galaxiex drew it himself, and is involved in this thread, I respect his decision if he wants to keep it at SS Guitar forum only.

[misterc57]

Attached are the modified schematics from Galaxiex on SSGuitars.

[galaxiex]

For good measure, here are the layouts I made...






Here is the reverb driver board I made/added to drive a full size tank instead of the original piezo tank.

[galaxiex]

And a few pics...

[galaxiex]

I am now a member. Galaxiex, that amp is a beauty! Did or do you have any hiss or noise issues?

I don't remember....

It's been a long time since I plugged this amp in.....

I still have it but packed away in the basement.

Faulty old guy memory says it "might" have some mild noise issues, but nothing I thought worth trying to fix.

I really should dig it out and give it another go...

[galaxiex]

I don't remember....

It's been a long time since I plugged this amp in.....

I still have it but packed away in the basement.

Faulty old guy memory says it "might" have some mild noise issues, but nothing I thought worth trying to fix.

I really should dig it out and give it another go...

So I got this amp out and played it a bit....

No noise issues other than a bit of hiss that increases with the volume control, as you would expect.
At full volume with no guitar signal of course the hiss is quite obvious, but its what I would consider "normal" for an old amp loaded with Ge transistors.
While playing the hiss is not noticed.
No crackles or other odd noises.

Overall this amp actually sounds "quite good", again, considering what it is.
Really nice clean sound at low "bedroom" volume.

I was playing it through a small 2X8 cab loaded with Jensen MOD speakers.

[galaxiex]

Looks like we don't have a pic of what this amp looks like, so here's a front pic...

This is from the ebay listing where I bought this...

I did clean it up a bit....

[misterc57]

Hiss I can live with. I would like to get rid of the crackling which sounds like poor AM reception. Comes and goes constantly and I think even with the volume at zero.

[galaxiex]

Hiss I can live with. I would like to get rid of the crackling which sounds like poor AM reception. Comes and goes constantly and I think even with the volume at zero.

Well... in some earlier pics your circuit boards look rather dirty...

I would start with cleaning those up.
The general dust and filth can cause unwanted conduction between components.

I think I use isopropyl alcohol and a soft nylon brush to scrub mine squeaky clean.

There are also spray cleaners specifically for cleaning circuit boards.

I pulled the boards completely out (label EVERYTHING, take lots of pics!) and scrubbed them really good.

I have an air compressor so also blow them off to dry the cleaning product.

Poor solder joins will also cause crackling noises.

[misterc57]

This isn't clean enough?



Joking....

I will circle back and try more cleaning

[galaxiex]

This isn't clean enough?



Joking....

I will circle back and try more cleaning

Ha ha,

Yeah... judging from what you started with... I'd say this amp was stored outside in a mud storm.

Quite possible there are many compromised/corroded solder joints.

If it were mine, I'd certainly pull ALL parts and boards from the chassis and super clean EVERYTHING.

Then on re-assembly. I'd re-solder pretty much everything.

It's a LOT of work and needs patience. ..... This is something I actually enjoy doing...

Some folks might look at it as.... "it's just a cheap crappy old amp with little to no value, why bother?"

.... but again, I like fixing up this old junk.

Polishing a turd... if you will...

[galaxiex]

I should mention...

Be careful cleaning the copper trace side of the boards.

Sometimes the copper is not well bonded to the board, and it's easy to lift the tracks.

[galaxiex]

Any news on this?
Did you get it cleaned up?

[misterc57]

Working on another project at this time. I will circle back to the Teisco but it may be a while. Thanks for checking in. MarkO