On 2017/02/27 3:13 AM, wrote:
On Monday, February 27, 2017 at 12:44:01 AM UTC-5, John Robertson wrote:
On 2017/02/26 4:38 PM, wrote:
On Sunday, February 26, 2017 at 5:06:38 PM UTC-5, John Robertson wrote:
I have an older monitor from a video game - and it has a jitter on the
horizontal lines on the screen (vertical is locked), yet I don't see
this jitter on the H Sync. Using a signal generator (Cross-Hatch, Dot,
etc.) and all outputs are the same. Game source also shows same jitter
on same screen.

It is not the WICO monitor signal generator as other B&W monitors show a
locked image.

Schematics he

http://www.flippers.com/pdfs/TEC_TM-...23_Monitor.pdf

Monitor has been recapped. Horizontal does lock, but jitter still present.

Suggestions appreciated!

Thanks,

John :-#)#

You said it "has a jitter on the horizontal lines on the screen (vertical is locked)". Just want to be clear. Do you mean to say the horizontal lines from the generator are jittering up and down indicating a vertical problem?


The monitor has had all electrolytic capacitors replaced, along with
most of the mylar ones.

We use Panasonic caps for electrolytics.

No, the lines are jittering sideways - indicating a horizontal problem.
If I adjust the horizontal control the jittering stays much the same as
the picture shifts sideways until it loses the lock.

John :-#(#


I wonder if you're describing what we used to call "piecrusting". Most of that was was from leaking HV. Remove the HV rectifier and see if there's any green schmutz in the contacts. Any corrosion will cause arcing.


Sorry, been busy. The diode is soldered directly to the HV leads. So a
bad connection is out. The HV probe does not show any obvious signs of
jitter, but I suspect that would be the case seeing as the tube is a
giant capacitor and would smooth over most noise.

I also pulled the LOPT/Flyback and did both a ring test and a leakage
test - it passed both just fine, good ring count, and no appreciable
leakage using my old Heathkit R/L/C Bridge Cap checker (1960s - with
Magic Eye tube!).

Additional comments in response to other posts on this topic...

Thanks,

John :-#)#

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