Re: TM506

Michael W. Lynch

On Thu, Jul 23, 2020 at 04:10 AM, Colin Herbert wrote:

I think you have maybe made an error in your description of the "PS503A does
not use the pass transistors". Tek were a bit naughty in not putting blue
boxes around them on the schematic in the Service Manual. When you think about
it logically, since the PS503A can supply up to 1.0 A in a high-power bay and
is limited to 400 mA in a standard bay, it stands to reason that it _must_ be
using the pass transistors. Perhaps you simply got the plug-in ID wrong (a

Unfortunately, I forgot about the "logic" part and and simply forged ahead, trusting that TEK would indicate the Pass transistors with the outlined Blue Box in the schematic like so many others. I "assumed" that since there was no such indication in the schematic that the plugin did not utilize the mainframe Pass Transistors. Just a boneheaded error and case of speaking before thinking logically. I learned something new from that mistake.


Michael Lynch
Dardanelle, AR

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