01-08-2022, 03:07 PM
I recall that in one of my Tandems all my voltages were also low but the set worked fine so I just let it go. As you mentioned, I typically pull the boards out and do a total rebuild since these are difficult sets to troubleshoot.
The voltage doubler uses the two capacitors to build up charge that gets added together to create B+. If the capacitance is too low to meet the load, B+ will drop. Likewise, if the internal resistance (ESR) of the cap is high, B+ will drop.
A simple thing to try is tack a capacitor in parallel with C1 and C2 and see if it brings B+ up.
Also, can measure the total current draw of the set? It should be 170 watts or 1.65 Amps according to Sams.
The voltage doubler uses the two capacitors to build up charge that gets added together to create B+. If the capacitance is too low to meet the load, B+ will drop. Likewise, if the internal resistance (ESR) of the cap is high, B+ will drop.
A simple thing to try is tack a capacitor in parallel with C1 and C2 and see if it brings B+ up.
Also, can measure the total current draw of the set? It should be 170 watts or 1.65 Amps according to Sams.
