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I actually own 3 Compass IB77 one working 77auto, one working 77pro and
a non working 77pro.
While trying to find the cause for the non-working 77pro, I noticed that
my 77pro's have different PCB boards with different wiring.
Who knows more about those modified 77's?
The serials are:
n° B349 for the non working unit (board n° 000203)
n° 709 for the working unit (no board number)
Following the serials, I guess that there is a later B-series.
In fact, I want to repair the defect unit, maybe someone can give me a hint.
The symptoms are the following:
At battery check, the A-pack does display empty batteries, B and C packs
seem to be OK.
I inserted new batteries in the pack and checked again, the check failed
in the same manner.
There are no broken wires or contacts.
At closer view, I noticed that the meter needle goes to the negative values (goes left to 0).
I supposed a wrong wiring and changed polarity of the battery pack, I got as a result the same display.
My following step was to test the current on the contacts of the meter.
I got the following readings:
battery check for the A-pack was - 0,120 volts
battery check for the B-pack was + 0,091 volts
battery check for the C-pack was + 0,089 volts
The negative reading for the A-pack persisted when I changed the polarity of the battery pack.
Has anyone an idea how I could solve this problem myself?
Kind regards from Luxembourg and many thanks in advance for your contributions,
Paul
a non working 77pro.
While trying to find the cause for the non-working 77pro, I noticed that
my 77pro's have different PCB boards with different wiring.
Who knows more about those modified 77's?
The serials are:
n° B349 for the non working unit (board n° 000203)
n° 709 for the working unit (no board number)
Following the serials, I guess that there is a later B-series.
In fact, I want to repair the defect unit, maybe someone can give me a hint.
The symptoms are the following:
At battery check, the A-pack does display empty batteries, B and C packs
seem to be OK.
I inserted new batteries in the pack and checked again, the check failed
in the same manner.
There are no broken wires or contacts.
At closer view, I noticed that the meter needle goes to the negative values (goes left to 0).
I supposed a wrong wiring and changed polarity of the battery pack, I got as a result the same display.
My following step was to test the current on the contacts of the meter.
I got the following readings:
battery check for the A-pack was - 0,120 volts
battery check for the B-pack was + 0,091 volts
battery check for the C-pack was + 0,089 volts
The negative reading for the A-pack persisted when I changed the polarity of the battery pack.
Has anyone an idea how I could solve this problem myself?
Kind regards from Luxembourg and many thanks in advance for your contributions,
Paul