Hi,

Got this monitor for free and am poking arounnd inside of it.

Power supply outputs check good.

Unit powers up.

Using an isolation transformer for testing, I have voltage on the HOT and
deflection yokes. Removed HOT and it tests fine.

No B+ at the flyback. All voltages on the flyback are null and void.

The heater pins glow however I get no raster on the screen at all. I
thought I had HV at first however I believe the static was from the degauss
coil.

Of course, I have no schematic or service literature.

Ideas?

Kirk S.

Do you have the proper supply voltage to the HOT?
Is the collector of the HOT, not having an open bias?
Are all the outputs of the power supply properly verified?
Are there horiz scan drive pulses reaching the HOT from the scan gen?

--

Jerry G.
======

"Kirk S." wrote in message
...
Hi,

Got this monitor for free and am poking arounnd inside of it.

Power supply outputs check good.

Unit powers up.

Using an isolation transformer for testing, I have voltage on the HOT
and
deflection yokes. Removed HOT and it tests fine.

No B+ at the flyback. All voltages on the flyback are null and void.

The heater pins glow however I get no raster on the screen at all. I
thought I had HV at first however I believe the static was from the
degauss
coil.

Of course, I have no schematic or service literature.

Ideas?

Kirk S.

Jerry,

I'm a novice, so bear with me please...

One hand in pocket, one lead clipped to cold ground, isolation transformer
in use, all but tip of other lead taped for insulation.

All outputs from SMPS are clean of AC and DC matches markings on PCB.

I followed the +210vdc to the HOT (actually a transformer near the NOT).
Attempting to read voltages at the collector and emitter freak out my meter.
Makes me believe there is activity. It has a separate damper diode on the
board which also tests ok. I get a reading on the base of about 0.4 vdc. I
have a scope however I'm apprehensive to hook it to anything. I've just
used it to probe digital circuits; never anything with voltage. I should be
able to hook it to the base of the HOT and see the horizontal pulses,
correct? I understand that I don't want to connect it to a hot ground (line
voltage).

Am I correct in the assumption that manufacturers label different circuits
with different numbers? ie. IC4xx, R4xx, Q4xx, C4xx is one area
(Deflection on this monitor) and IC9xx, etc. is another? The flyback is
T901 and I'm looking around (with monitor off) at the 9xx related components
to see if I can find something.

Can I safely look at the yoke voltages with a scope? Or do I need to find
them before they are amplified?

Interested in learning yet very respectful of the voltages inside. I also
have a high voltage probe so I can test the anode voltage if necessary. I
have fixed a couple arcade monitors however the flyback is connected to the
HOT on those and this multifrequency monitor is quite a bit more
complicated.

Thanks!

Kirk S.
"Jerry G." wrote in message
...
Do you have the proper supply voltage to the HOT?
Is the collector of the HOT, not having an open bias?
Are all the outputs of the power supply properly verified?
Are there horiz scan drive pulses reaching the HOT from the scan gen?

--

Jerry G.
======

"Kirk S." wrote in message
...
Hi,

Got this monitor for free and am poking arounnd inside of it.

Power supply outputs check good.

Unit powers up.

Using an isolation transformer for testing, I have voltage on the HOT
and
deflection yokes. Removed HOT and it tests fine.

No B+ at the flyback. All voltages on the flyback are null and void.

The heater pins glow however I get no raster on the screen at all. I
thought I had HV at first however I believe the static was from the
degauss
coil.

Of course, I have no schematic or service literature.

Ideas?

Kirk S.

Jerry,

I found a bad fusible resistor on the B+ line to the flyback. I just needed
to look at it differently and follow the path back from the flyback to the
power supply. Will check other components in the area as well.

Kirk S.
"Jerry G." wrote in message
...
Do you have the proper supply voltage to the HOT?
Is the collector of the HOT, not having an open bias?
Are all the outputs of the power supply properly verified?
Are there horiz scan drive pulses reaching the HOT from the scan gen?

--

Jerry G.
======

"Kirk S." wrote in message
...
Hi,

Got this monitor for free and am poking arounnd inside of it.

Power supply outputs check good.

Unit powers up.

Using an isolation transformer for testing, I have voltage on the HOT
and
deflection yokes. Removed HOT and it tests fine.

No B+ at the flyback. All voltages on the flyback are null and void.

The heater pins glow however I get no raster on the screen at all. I
thought I had HV at first however I believe the static was from the
degauss
coil.

Of course, I have no schematic or service literature.

Ideas?

Kirk S.