Getting a broken pin out of a B8 Valve Holder.

[ppppenguin]

Qucik and dirty answer.

Leave the valve in situ for the heater. Then fit silicon under the chassis.

[boater sam]

Having tried a couple of suggestions, I find that the broken pin will not push through from the underside, so I can oly conclude that the tag end snapped off below the twisted part of the pin, and that it's stuck fast due to the twist.  Re-reading your suggestion, Sam, I'm just wondering what inserting a small screw at the tube end will achieve, but if I can find a small-enough screw I'll give it a try.  Of course if I can determine which, if any, if the unused pins are internally connected to the anode, I could simply rewire the anode connection to  the pin in question instead.

I thought if you got a grip with a thread in the socket you could use it to pull the contact out.
A silicon diode/s is certainly a solution, or as you suggest, de-base a rectifier valve and transfer the anode? to another pin but making a special, heaven help the next repairer!
But if you connect across under the base to another unused pin it would be obvious.

[Old Sparky]

I'm coming round to the idea of using a silicon diode, Jeffrey. A 1n4007 or UF4007 would obviously be more than adequate, with, if necessary an additional series resistor. Sam, if I located to which other pin the rectifier's anode is connected (should be easy with my DMM on low ohms range), then I would include a sketch showing which pin I'd used, and why I'd done so, but I'll have another go at removing the broken pin first.

[Kalee20]

What make of valveholder are they?

I have had a few McMurdo pins break... but never had any trouble getting them out ad transplanting a new one in.

If these are McMurdo valveholders, I can stich a B9A one in the post (same pins) and you can have 9 practice tries at getting the pins out, on the bench rather than stuck in the chassis! And with luck you will end up with 9 spare pins!

[ppppenguin]

There's alaready a 150R resistor in seres wih the rectifier on a DAC90A. Plus part of the dropper for voltages over 210V. The HT voltage is not critical so a silicon diode should be fine on its own.