Ampeg SVT 200t 4x10 combo "issues"

[Taylor_Bassman]

Hey everyone, this is my 1st thread.
(I hope I'm doing it right)
* Feel free to school me on a better process and/or way of doing things here.. thx
Here we go ........

OK... Recently I purchased a :
"Ampeg SVT 200t 4x10 combo" from a local pawn shop for the amazingly low price of $40 (yes you read that correctly) "$40" !!
It was originally $50 but the shop owner accepted $40 cuz he said the seller stated "The Amp Has Issues" ! and he didn't want to deal with it anymore.

At first, I brought it home, wiped it off a bit and discovered the entire unit is in REMARKABLE & prestine condition; I mean not even a scratch on it ANYWHERE !! beautiful shape...

However (lol)...
I discovered the issue(s) when I played thru it for about or about 5/10 mins and it sounded as if someone "pulled the plug (..Is the best way to describe it) cuz it just sorta fizzles out and dies. After 5/10 more mins, it comes back on and repeats the same thing; stays on, then cuts out after a few mins..

I've heard of problems with other solid state amps like this having similar trouble, but wondered if anyone else had or still has these issues with THEIR OWN Ampeg t200 ..and/or if any solution was discovered (?)

* My older brother is an Electrical engineer and has fixed every broken piece of gear I've owned for the 30+ yrs I've been playing, so I gave it to him to go thru it and see if he can discover the "issues" with it ...and just as I thought, it DIDNT cut out on him when he bench tested it, and he thinks I'm crazy now ..lol
--He told me "There's Nothing Wrong With It" ..When I CLEARLY know there IS !!!

Any insight out there ?

 

[Old Garage-Bander]

Hey everyone, this is my 1st thread.
(I hope I'm doing it right)
* Feel free to school me on a better process and/or way of doing things here.. thx
Here we go ........

OK... Recently I purchased a :
"Ampeg SVT 200t 4x10 combo" from a local pawn shop for the amazingly low price of $40 (yes you read that correctly) "$40" !!
It was originally $50 but the shop owner accepted $40 cuz he said the seller stated "The Amp Has Issues" ! and he didn't want to deal with it anymore.

At first, I brought it home, wiped it off a bit and discovered the entire unit is in REMARKABLE & prestine condition; I mean not even a scratch on it ANYWHERE !! beautiful shape...

However (lol)...
I discovered the issue(s) when I played thru it for about or about 5/10 mins and it sounded as if someone "pulled the plug (..Is the best way to describe it) cuz it just sorta fizzles out and dies. After 5/10 more mins, it comes back on and repeats the same thing; stays on, then cuts out after a few mins..

I've heard of problems with other solid state amps like this having similar trouble, but wondered if anyone else had or still has these issues with THEIR OWN Ampeg t200 ..and/or if any solution was discovered (?)

* My older brother is an Electrical engineer and has fixed every broken piece of gear I've owned for the 30+ yrs I've been playing, so I gave it to him to go thru it and see if he can discover the "issues" with it ...and just as I thought, it DIDNT cut out on him when he bench tested it, and he thinks I'm crazy now ..lol
--He told me "There's Nothing Wrong With It" ..When I CLEARLY know there IS !!!

Any insight out there ?

That's the same as when you take your car to the shop and it won't make that funny noise while you're there.

Have your brother start with a very thorough internal visual inspection, including a lot of wiggling/jiggling of components and solder joints. Be sure he gets a good look under the chassis while doing this. Turn it on its side slowly and listen for anything that might be rattlin' around loose. Odd things like a small crack in a circuit board or a cold solder joint can cause intermittent problems.

 

[Bass_Pounder]

Does the amp have an FX loop ?

If so, plug an instrument cable from the send to the return and see if the problem goes away. If so, the jacks need to cleaned.

 

[Taylor_Bassman]

Very interesting !

I was told everything regarding this, and related problems with this amp are due to more of a circuitry problem, rather than dirty input Jack's or something as simple as that.

My brother had told told me he went thru every inch of the board & connections & it is all solid; nothing burnt or loose. He is VERY good at what he does and is extremely knowledgeable in checking and repairing things of this nature.
He has worked in electronics his whole life and I DEFINITELY trust his word, as well as his work.

* I'm not sure if it has an "fx loop" as I removed the amp section and gave it my brother several weeks ago; plus I've only owned it for a few months and (I'm sorry to say..) I'm not THAT familiar with the unit functions/input & outputs & accessibility.

(( I'm wondering how much differently manufactured the 200t "HEADS" are from the COMBO amp sections (?) ))

When this amp IS running properly (for the 5/10 mins at a time) it is the most warm and punchy amp (for a 300 watt combo) that I've played thru in quite a while ! Sounds like the typical "Ampeg" SS sound/tone.

I'd sure like to have it repaired once and for all some day so I can rely on it NOT cutting out on me. It's not worth very much in its current state.

 

[JimmyM]

The effects loop is on the front panel.

 

[Bkpettengill]

Bought one for $99 + tax earlier this month. The potentiometer (70-103-28 stacked) was broken off flush with the panel. Powered it up & no sound. Fiddled with the on/off power button and if I held the power button barely on, worked like a charm. Replaced the broken potentiometer but now, it won’t even power on. Found a schematics tonight so hopefully it’s up & running in a week or so. I’ll let ya know. If it comes to it, I’ll take the power part to an older guy I know to point out what I didn’t hook back up for about a $20 bench fee. lol

 

[Taylor_Bassman]

Like I said in my original post, when I got mine, the sound keep cutting on and off and I didn't know why. It worked, but it was intermittent...
My brother is an electrical engineer, and he damn near deoxidized the whole amp. The Input jacks were very bad. He told me that is the very reason it was cutting on and off !!
He went through and cleaned up every single connection, and all dial controls.

The entire cabinet section and speakers are in Immaculate shape and I still can't believe how clean it is. After getting the amp section straightened out, it is a very very nice warm, and also unique combo amp. - I love it.

Let me know if you have any trouble repairing it, and/or getting any schematics... as im SURE my brother would have some insight on fixing it.

-- We can get it fired up for ya' !!