[Jukebox-list] Hot Plate (6973)

[Carl Haines]

Jay Hennigan wrote:
> I never even saw a delivery attempt on the admin interface here.  Please 
> try to send in plain text if at all possible.

The last time I checked Yahoo only offered web mail for free and if you 
wanted POP3 access you needed to pay an annual fee.  Maybe David 
Breneman could try posting a message to see if it comes through.

> On the 222 series Seeburg amplifiers, be sure that the negative voltage 
> supply is working and producing voltages reasonably close to spec.  This 
> power supply is a simple half-wave rectifier.  The early ones were 
> selenium.  It supplies both the transistor preamp as well as bias to the 
> 6973 output tubes.  If this power supply fails or is marginal, the tubes 
> will get cherry red and eventually take out the output transformers.

The amp is a SHFA2 rather than a SHFA1, not that it matters that much. 
This makes three votes for the voltages etc.  I was reasonably certain 
that the problem was with this particular tube, but as a sanity check I 
went and checked the voltages.  All were within a few volts of spec.  I 
should have mentioned that I suspected that this tube may have been 
damaged by overheating prior to my recapping the amp.  I am confident 
that the tube is bad.  I guess the innards have been distorted by having 
been overheated.  I will recheck everything once I get a real set of 
6973 tubes and give it a full workout and see what happens.

Carl Haines