SR-52A rebuild project (SR-52A 942058 LTA4176)

[albertofenini]

Differences between SR-52 and SR-52A, testing Vdd, Vgg, Vss, Vbatt

Hello Everyone, few updates for today :

we are almost certain that this unit is a SR-52A, while the two we restored are most probably SR-52 REV. D thru L

we tested all of the voltages from this unit and we compared the values with those from a working SR-52
the differences are
1. a SR-52 uses a TMC0524 where a SR-52A uses a TMC0534
2. a SR-52 uses a CD4011 AND a SN96239 where a SR-52A uses only a CD4011
but all the voltages measured at every IC where identical between the two units
we have also noted that Vgg in the documentation is expected to be -15 V and actually is about -12 volts for both units
while Vdd in the documentation is expected to be about -10 V while in both units is about -6.24
Vss is about Vbatt for both units so we believe is ok

we attached a scope and we have found the SR-52A (the one that doesn't work)has a good Clock 1 and Clock 2 signal
exactly as the working SR52 in all the points where it is supposed to be

current consumption is also identical between the two and is about 170 mA when showing a 0 (or for the SR-52A what is should be a 0)

We have found however different waves around the TMC0501 in the non working unit
However, since this is the area where the PCB was badly ruined, before removing and trying to replace that chip we would
appreciate some suggestions on the possible cause of non working.

Any idea ?
Thanks for help !!!
Take care !!!