WB8TSL:
.... The 8663 supply is pretty much the same.
The 20 V reg is pretty simple and can be traced out if needed. But check that the 20 V is not shorted to ground. The smoke makes me think someplace in the unit a tantalum has turned very black.
The supply senses current and does limit.?
Good luck
That helped, my 8662A works again. It did cost me most of the weekend. Some
50 screws are still to be re-inserted and my fingertips are sore because of the
many sharp edges on the SMCs.
It wasn't the power supply. It was one of these light-blue tantalums on A4A3.
I could not find the A4A3 drawing. In the 8663A this is something unrelated.
I wanted to see the source of the black smoke but could not find it, although
I opened all the plug-ins. The shorted tantalum looked completely innocent.
I Widlarized it carefully.
In one of the x reference lists, the linear regulators were translated as CA3020,
a double long tail pair. It is LM204 / LM205.
As a side effect, this 0-160MHz-320MHz-480MHz-bug is gone. No idea why.
I also replaced the incontinent NiCd battery block. It is the same type of
block that used to be in my HP-35 in a previous life. For the moment,
these are Eneloops until I get NiCds. Those are quite rare here now.
I also used a new battery holder.
Thanks to all and 73,
Gerhard DK4XP
