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realfoneguy realfoneguy is offline
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Quote:
Originally Posted by Luca T. View Post
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Jim Yanik wrote:

| Basic modules of any scope;
| 1. power supplies;*first to be checked*

This seems to work, at least the values that i could read on some
test-points were correct, unfortunately i do not have a service manual
or anything that would tell me what the correct voltages of other
test-points are (i could only test the ones where their supposed voltage
values is written on the board).

| 2. vertical deflection circuits
| 3. triggering
| 4. sweep(horizontal) deflection
| 5. CRT unblanking and intensity control
|

Sigh, i am absolutely ignorant about oscilloscopes and without a manual
to tell me exactly what to do i am lost

| If you can access the vertical and horizontal deflection CRT pins,you can
| short them (vert-vert,H to H) and see if you get a trace or spot on
screen.
| If so,then you have a problem in the corresponding circuit.(short
verticals
| and get trace=bad vertical amp).short horizontal pins and get spot=bad
| horiz or triggering)
|

I wish i knew where those pins are, i do not really feel like to
short-circuit random pins. Sigh... anyone knows where i could find the
service manual of this oscilloscope without having to buy a copy?

Thank you for your answers,
~ Luca
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I am not sure if you found your issue as yet, but I had the exact same issues. No trace, no screen illumination. The schematic, service and users manual is located at the Agilient web site. No Charge and in PDF format.
I studied the guide and found that if 15 volts of any flavor is an issue, the 120 volts will go awayt shutting down the HV cage. This is where the illumination and trace are provided. (HV Supply). So i printed off just the LV power supplu schematic. and found that the 122 volts was at 30 Volts. That told me shutdown. So I measured 43, ok 5 volts OK. -15 volts NOIPE .5 volts POSITIVE. Certainly knew this was wrong, so on the schematic I see a 3500MFD cap at 30 volts. Right across the output of the bridge rectifier. Checking this it was shorted at 1meg ohm. I am going to get one from someone now. To provce it was the -15 volt supply, I removed the triple connector board and measured the 120 volt line. Sure enough it came back. The -15 had risen and the IC3 got hot to touch. Testing the transistor, it was OK. I hope the IC is OK. I will just get a new cap now. Don't plug in the scope with the cap out of the circuit. There is 20+ volts there that will probably take out the IC or the diode zener for 10Volts. Brad