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Jitter on locked horizontal part of image - B&W transistorized TECmonitor
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 :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
Jitter on locked horizontal part of image - B&W transistorizedTEC monitor
On 26.02.17 23:06, 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 :-#)# Sounds like the power supply is starting to fail. Check the caps there, for bulging ca[p tops, and replace them. While it is open, also check around the high voltage area, and if you smell ozone, something is producing sparks. Clean and replace bad caps. |
Jitter on locked horizontal part of image - B&W transistorizedTEC monitor
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 :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." 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? |
Jitter on locked horizontal part of image - B&W transistorizedTEC monitor
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. |
Jitter on locked horizontal part of image - B&W transistorized TEC monitor
On Sun, 26 Feb 2017 14:06:31 -0800, 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 :-#)# If the problem isn't HV arcing, check or replace parts from pin3 of the flyback including the 2 AFC diodes D401 and 402. The diodes on this line I'd just replace. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
Jitter on locked horizontal part of image - B&W transistorized TEC monitor
"Chuck" wrote in message ... On Sun, 26 Feb 2017 14:06:31 -0800, 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 :-#)# If the problem isn't HV arcing, check or replace parts from pin3 of the flyback including the 2 AFC diodes D401 and 402. The diodes on this line I'd just replace. A dry joint is also possible, or a noisy part burned resistor dropping feedback from a flyback winding to the phase discriminator. Arcing usually isn't too hard to see - corona discharge can be, a faint purple haze around any sharp pointy bit at EHT potential. Sometimes you have to view the chassis with the light turned off to see it. |
Jitter on locked horizontal part of image - B&W transistorizedTEC monitor
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 :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
Jitter on locked horizontal part of image - B&W transistorizedTEC monitor
On 2017/02/27 8:59 AM, Chuck wrote:
On Sun, 26 Feb 2017 14:06:31 -0800, 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 :-#)# If the problem isn't HV arcing, check or replace parts from pin3 of the flyback including the 2 AFC diodes D401 and 402. The diodes on this line I'd just replace. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus Hi Chuck, Thanks for the suggestions - I tried all that and no improvement in the image quality. I used a couple of 1N43 Germanium diodes in place of the AA143s, but (as I said) no change. The only place I can 'see' a problem is when I monitor the cathode of the picture tube. The horizontal section appears quite stable with no flicker showing on my fast Tectronics scope. Images: Video - jitter on screen: http://www.flippers.com/images/Horiz...EC_monitor.MOV Scope - base of Horizontal drive: http://www.flippers.com/images/Horizontal-drive-@-base Scope - base of final video amp: http://www.flippers.com/images/Base_of_final_video_amp Schematic - base of final video amp (wrong version of schematic here though): http://www.flippers.com/images/Base_...ideo_amp-scope Appreciate any other suggestions. I haven't yet tried replacing the resistors in the feedback loop, however the jitter doesn't show in the loop... Thanks! John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
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