I load tested my recent TP340A acquisition and it did just fine. The only thing was an occasional slight flicker of the fault light on Source A.
Opening it up, I found that R137 was burnt to a crisp. An easy replacement and the fault light flicker disappeared.
In an effort to see what this 1K resistor was doing and why it might have been burnt, I turned to the schematic. The schematic found in the TP340A manual I've downloaded from KO4BBs manual archive is almost illegible. That site also has a slightly better quality scan of the TP340 manual which is somewhat legible. But alas - no R137 on that model. In any case, it appears to be part of the crowbar circuit. Inspection did not reveal any other obvious issues and none of the always suspect tantalums appear shorted, so hopefully it will remain problem free.
If anyone has a clearer version of the manual or schematic, it would be much appreciated.
It was impressively clean inside and aside from the one burnt resistor, appeared almost brand new. It's interesting seeing some of the component changes in
bitseekers newer unit. Best I can tell from date codes is mine was manufactured in the mid 1980s.
I'm really quite impressed with this unit. There are not published specs on the noise and ripple, but on my testing it was in the neighborhood of 50 uV, similar to my PD 2005a, 2010 and my HP 6114 and 6115s.