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Author Topic: scopemeter PM95  (Read 1236 times)

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Offline david69Topic starter

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scopemeter PM95
« on: January 11, 2021, 08:40:18 am »
Hello,
Can I ask about battery charge protection circuit in PM95 ?
The two 2SK974 should switch groud to battery before charging.
There are switch off in Power OFF scopemeter?,
The V2541 has emiter -8V and base,colector -7,5V against groud,
V2543 has -7,3V on common pin... power supply is switched off.
The battery pack is broken? There is 5,4V
Thanks
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #1 on: January 13, 2021, 09:42:14 am »
Hello,
I have replaced all elyts on analog board. The charging battery is working.
The supply is working. Chanel B is working, but chanel A + red banana is
not working :( I have tried signal 1kHz/100mV Vpp to chanel A in scope mode, but on
point TP207 no signal, there is switched on/off signal in meter AC option and
when signal is connected to red banana, where I am looking for errors?
Thanks ....
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #2 on: January 13, 2021, 12:35:16 pm »
The service point TP207 is active in SCOPE mode, when input signal
on chanel A is about 1V Vpp but display shows no signal...
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #3 on: January 13, 2021, 04:37:06 pm »
The test points both analog/digital are ?OK? any strange, scopemeter works partly in scope mode on chanel B, but during operation freeze :(
"Instrument must be reset" .....
Do You think that flash is broken? There are some firmwares for PM95??
or RAM?? etc...
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #4 on: January 14, 2021, 07:38:54 am »
The SET AUTOMATIC SCOPE function is not working
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #5 on: January 14, 2021, 03:59:57 pm »
display shows signal connect to channel B, but there is switched channel A,
Hybrid OQ0308 ??
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #6 on: January 15, 2021, 06:26:25 am »
I will replace all analog switch 4316 in Attenuators and see?
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #7 on: March 12, 2021, 03:39:16 pm »
good news, point TP107 and TP207 has same signal, AD converts data on both
chanel A and B, but display still shows only signal in chanel B :(
and scopemeter doesn`t work, resistance shows 6 Ohm with opened input? but
pulses are changed by variable resistor, digital control board has broken firmware?
Or Where is fault? Thanks David
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Offline david69Topic starter

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Re: scopemeter PM95
« Reply #8 on: March 13, 2021, 01:36:05 pm »
Signal CHANA is missing behind R1232 parallel with C1222 on pin 13 of OQ00308 :(
Signal processor is working, I have tried change capacity from 120pF to 1nF without
efect...
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