Interpret Waveform from Oscilloscope

[ken kantor]

please remove me

 

[ken kantor]

I was careful to follow the service manual to the tee. Clipped mini-grabbers with leads to the fuse brackets and the meter never was inside.

And the fuse was removed during the test?

Of course, the inability to set the bias could also have been a symptom of something wrong in the circuit. My comment was just a thought, not a diagnosis.

(What means: the meter never was inside?)

-k

 

[Robot17]

Sorry I'm a taking a bit. Had a car problem today..

And the fuse was removed during the test?

-k

The service manual called for removing both, testing f002 and then powering down and replacing it, powering up and testing f003 which is what I did.

Of course, the inability to set the bias could also have been a symptom of something wrong in the circuit. My comment was just a thought, not a diagnosis.

Quite so. Not trying to be obsequious but your random thoughts are likely to be better than My diagnosis by a factor of at least 10.

(What means: the meter never was inside?)

For safety I ran mini grabber leads to the DMM outside of the case to minimize the risk of hitting something on accident. I connected the wire leads with out the DMM attached (no power) and attached those to a set of leads in a helping hands carriage. Itry to be very careful when interrupting a circuit.

Bot

 

[ken kantor]

Sorry I'm a taking a bit. Had a car problem today..


The service manual called for removing both, testing f002 and then powering down and replacing it, powering up and testing f003 which is what I did.
Quite so. Not trying to be obsequious but your random thoughts are likely to be better than My diagnosis by a factor of at least 10.
For safety I ran mini grabber leads to the DMM outside of the case to minimize the risk of hitting something on accident. I connected the wire leads with out the DMM attached (no power) and attached those to a set of leads in a helping hands carriage. Itry to be very careful when interrupting a circuit.

Bot

OK, well, I'm pretty sure you have a bad output device, or a broken connection near it.

-k

 

[Robot17]

Thanks. It takes me a bit to noodle around with this stuff because it's not immediately obvious to me what you guys are talking about.

I tested the 1361 board's resistors and found several out of spec.

 

[Robot17]

I did a test of the transistors on the F 1358 board. My DMM reads .998 V or so in Diode test mode usually (sometimes it reads OL) when nothing is attached to the leads. Don't know what that is about (POS?).

All the C1060 transistors test fine.

Any clues appreciated.

Bot

 

[ken kantor]

I did a test of the transistors on the F 1358 board. My DMM reads .998 V or so in Diode test mode usually (sometimes it reads OL) when nothing is attached to the leads. Don't know what that is about (POS?).

All the C1060 transistors test fine.

Any clues appreciated.

Bot

What does the meter read on the same test, but with nothing connected to the leads?

-k

 

[Robot17]

.998v or so. It varies but is in the .9 - .990 range.

I probably wasn't clear Ken. I think my transistor test results (see pdf) that return in the .9 v range are just the meter itself and are most likely an OL reading but the meter is off for some reason.

Bot

 

[Jon_Logan]

.998v or so. It varies but is in the .9 - .990 range.

I probably wasn't clear Ken. I think my transistor test results (see pdf) that return in the .9 v range are just the meter itself and are most likely an OL reading but the meter is off for some reason.

Bot

For that "0.9" reading you get, you might want to measure something known like a diode you might have laying around. The first thing to do is to gain some confidence in your test equipment so that results can be interpreted solidly.

"0.9" might be a good number, but it's a little weird but maybe just how that meter does it. Make sure that the meter's battery is in good shape. Most meters will read a diode (or transistor's) junction with an actual Forward Voltage (VF) and you should expect 0.6~0.7 (volts).

 

[Robot17]

For that "0.9" reading you get, you might want to measure something known like a diode you might have laying around. The first thing to do is to gain some confidence in your test equipment so that results can be interpreted solidly.

"0.9" might be a good number, but it's a little weird but maybe just how that meter does it. Make sure that the meter's battery is in good shape. Most meters will read a diode (or transistor's) junction with an actual Forward Voltage (VF) and you should expect 0.6~0.7 (volts).

Will do. Thanks