#91

Out of Production Hardware / Lost trace line on 2700

Last post by P3_Orion - September 24, 2024, 10:50:44 AM

Howdy,

New user here trying to get help with a failed 2700. The unit was working but the trace line was starting to go crazy with random zig zags and wild fluctuations in signals. It has now mostly stopped working although it does randomly show an inconsistent trace line that might span only an 1/8 of the screen width and then shoot across and retreat or just go away completely.

I asked Huntron for schematics or repair manual without success, although they must have them if they repaired their own products in the past. But I understand its all proprietary so here we are trying to figure this out from scratch.

Since the trace line from my understanding is an AC output signal, I have been starting from the connector trying to work back. I am only showing AC voltage at the probes in the mV range. I checked voltage at the 2w output power resistor. Again only showing erratic mV readings, this traced back to an output buffer (OpAmp, 634U) that I believe controls the output current. I again have erratic voltage in and out signals and the chip does have a proper DC supply voltage of I believe was 15v.

Since the input voltage is low and erratic I think the problem is further back, but I could spend forever trying to trace back to the transformer I am assuming. I do see there are 7 Voltage Regulators, 6 LM317 Mosfet style, all warm without to the touch and consistent so assuming they are all doing there job, then their are 2 'jellybean' BJT style voltage regulators that I can only assume work. There is no way to test them live as the risk of shorting is too high. I see test points all over the board, but again without a schematic I have no idea what any of them are tied to.

I didn't mention this before but the entire screen works normally and all the buttons appear to function correctly and the unit was working before the trace line become erratic and now mostly non existent.

Hopefully this might be a common failure and someone has a magic bullet to hand me

Thanks Again!

#92

Out of Production Hardware / Re: Protek 1

Last post by admin - September 17, 2024, 06:31:43 PM

The HV power supply may have failed. Does it have a large silver module on it (Electronetics, I think)?

#93

Out of Production Hardware / Re: Protek 1

Last post by volken - September 13, 2024, 08:50:36 AM

Yes the unit always worked very well

#94

Out of Production Hardware / Re: Protek 1

Last post by Al1234 - September 12, 2024, 05:35:32 PM

hi, was this a working unit you've had and problem just happened or you got this unit as is?
do you know if all the boards are there inside. if all in place.
I remember I had no trace on a KJ3, I made some adjustment for trace alignment in both the advanced mode and regular and on the inside board (3 potentiometers on the tube board) turned up the intensity and move right, left, up, down and trace appeared.  I think one of those potentiometers make the trace completely fade away.

#95

Technical Support Announcements / Huntron Technical Resources Li...

Last post by admin - September 11, 2024, 07:48:10 AM

We recently compiled a comprehensive list of technical resources available online to Huntron users. It includes links to tutorials, manuals and even product FAQs. If you have any resources that would be useful to add, post a link in this forum thread.
Huntron Technical Resources List

#96

Out of Production Hardware / Re: Protek 1

Last post by admin - September 09, 2024, 06:21:54 AM

This post from JVTHorsley may be useful.
https://huntron.com/forum/index.php?topic=191.0

#97

Out of Production Hardware / Re: Protek 1

Last post by fetron - September 05, 2024, 09:57:04 AM

Hello Volken!

I would like a picture of the CRT HV power supply PCB !  (Protrack, inside on the back wall)

Thanks.

#98

Out of Production Hardware / Re: Protek 1

Last post by admin - September 01, 2024, 10:13:33 AM

Also try adjusting the horizontal or vertical trace position. The trace may be off screen.

#99

Out of Production Hardware / Re: Protek 1

Last post by jvthorsley - August 30, 2024, 08:16:41 AM

Hi
Might be worth reprogramming the Flash Prom.
I have written about this on this Forum before.
Curtis (Tech support) can email you the program.

#100

Out of Production Hardware / Re: Protek 1

Last post by volken - August 30, 2024, 01:09:12 AM

Thank you yes I did this but there is no screen at all .