Internal screw loose, bleeding filter caps on 2/90/2

Power Amps 2/90/2
1

Hello Folks.

I just received a (purchased used) Fryette 2/90/2. There was a screw rolling around inside and so I need to bleed off the internal power before I go sticking my hands inside. Especially since I just used it… I do plenty of DIY amp building, but more Marshall style amps, so I know those like the back of my hand and usually would bleed off the power in basically any B+ point on the line by grounding it to the chassis with a 10k 10watt resistor.

Just looking at the photo (the amp is not in front of me at the moment), my initial thoughts are to ground from R103 which seems to be in place of a choke (??? is this correct ???). In the photo attached, the missing screw is circled in pink and the leg of the R103 that I THINK I need to ground (with a 10k/10W resistor of course) is squared in pink.

Any recommendations on the point to ground from and the point to ground TO (the chassis is painted, I assume I won’t have ground continuity - or will I ??)

Thanks much!

Regards,
Eric

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2

Hi Eric,

Welcome to the forum!

I hope you got everything figured out from our discussion. Let me know if all is well with this.

Thank You,

Terry

3

Thanks, Terry! I am going to fix it this weekend. I am 100% confident all will be good! Thanks!

4

I fixed it, but couldn’t get full B+ where we talked about, I ended up reading the full 500+ VDC off of the power tube pin, and the reservoir cap sharing resistors… other places I hoped I’d get the full voltage, I got HALF of what I expected. This was set at 60 watts, channel A, not in standby, all controls turned to zero. So I grounded from the top of the sharing resistors (whatever those resistors are called that are there to spread the power evenly between the two sets of parallel filter caps…).

Either way, screw replaced :slight_smile:

Thanks!