I'd like to share an email I got from W3PAL concerning the this:
I think you will need to remove the transformer.
To gain access to the Switch Board, remove both top and bottom covers and then
remove the 4 stainless screws and bolts that hold the transformer. Unclip the
transformer Molex connector and remove the transformer unit. Take care as
towards the front of the transformer there is a small disc capacitor connected
on the chassis which could easily be crushed by the heavy transformer.
Now you can work without hindrance.
Take the knob off the IP/VP switch – it’s held in with 2 small grub screws.
Unscrew the fine nut which holds the switch in place, and slide the switch out.
The switch is hardwired to the board, so the switch and whole board will now
come out as a single unit.
You’ll notice 4 small ‘Festoon’ type bulbs. They look like fuses but are not
and work differently.
Keep in mind that most circuits in this amp were designed very poorly.
Documentation is terrible and not consistent with each amp. Servicing this amp
can be a pure nightmare.
The 12VDC voltage regulator on the control board is only rated for 1A. The four
original bulbs draw 0.25A each. It's 1A for the light bulbs only. Everything
else overloads the regulator. They often fail because of this.
It's best to use 6615F bulbs that draw only 0.08A each. You can also try to
replace it with newer LED bulbs. Just google: festoon Sun Visor LED bulbs. Just
make sure that all four new LEDs don't draw more than 1/2A. I would add a small
capacitor across each LED bulb's terminals to eliminate any induced RF.
Thanks to Ivanov for that replay. While I may disagree with his assessment of
the design of the amp his info seems accurate and to the point.
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