SVT-6 PRO relay issues

[Mr_bibbles]

Hey Guys and Gals-

Got an SVT-6 pro on the bench. Came in with a blown t125 fuse on the filter cap board which I've replaced. I've kept it on my lightbulb limiter as I don't know what the issue is, but I have some pretty good signs pointing towards some sort of protection circuit or power issue.

1. Upon powering up, the amp takes about 40-60 seconds for the initial relay 'click' to turn on, no sound before this.

2. Relay will click, sound will shut off for just a moment if total level is above a certain point (master and gain both affect the 'trip') . Relay clicks back on instantly after the 'peak'

3. Produces decent sounding signal but problem remains through FX loop testing both ways.

4. Fans give one sad little turn every 15 seconds or so, but don't operate correctly. After shutdown the fans spin smoothly for a few seconds.

My guess is faulty thermal protection control elements or possibly something with the total power supply?? SS is not my forte, so any help pointing me in the right direction is appreciated!

Thanks everyone!

[52 Bill]

Is it possible that all of these symptoms are being caused by the light bulb limiter? How bright does the bulb light up?

Some amps will only work marginally with lowered power supply voltages.

[Mr_bibbles]

Good call bill!

Took it off the limiter, was able to light up the "peak" LED without tripping any relays. Fans sped up as I tested, eventually reaching a pretty good spin. Signal volume dipped to a very quiet level once or twice during the testing and there was some unwanted distortion (no relay clicking though), some of the preamp tubes seemed extremely hot (couldn't keep my finger on them for more than a second...) thoughts as to where to go?

[52 Bill]

Now try your FX loop test again. Is the preamp signal distorted? Is the power amp distorted?

[Mr_bibbles]

I resoldered some funky joints near the transistor chains and replaced one preamp tube after the Send/Return test and it sounds graet! Problem fixed, thanks a lot for the tip on SS low voltage relay interferance Bill I won't forget it.

[52 Bill]

I resoldered some funky joints near the transistor chains and replaced one preamp tube after the Send/Return test and it sounds graet! Problem fixed, thanks a lot for the tip on SS low voltage relay interferance Bill I won't forget it.

Glad to hear that it's working. Bad solder joints are a very common problem in these amps.