Jump to content

Photo

CV - Video Vertical Banding


7 replies to this topic

#1 onlyinajeep OFFLINE  

onlyinajeep

    Space Invader

  • 12 posts

Posted Tue Sep 12, 2017 10:02 PM

I recently picked up a ColecoVision, it works fine, but the picture exhibits some vertical bands in the color fill areas. You can see it in the green in the upper photo and the blue and red in the middle photo. The bottom photo is from a second unit using the same power supply, tv, and RF cable, which looks great. The PSU from the second unit was tried with the problem unit and nothing changed. I replaced the Radio Shack switch shown in this article with no improvement. I installed an RCA video out from this guy and, if anything, the bands are more prominent. Any idears on how to correct this would be appreciated.

 

thanks, Steve

 

ColecoColorBanda.jpg

 

 

ColecoColorBandb.jpg

 

 

ColecoColorBandc.jpg



#2 youki OFFLINE  

youki

    River Patroller

  • 2,259 posts

Posted Wed Sep 13, 2017 12:50 AM

did you try on another TV?



#3 onlyinajeep OFFLINE  

onlyinajeep

    Space Invader

  • Topic Starter
  • 12 posts

Posted Wed Sep 13, 2017 1:26 AM

Photos are on a Zenith System 3. A Sony Trinitron exhibited the same issue. My second ColecoVision looks great on either.



#4 nanochess OFFLINE  

nanochess

    River Patroller

  • 4,894 posts
  • Coding something good
  • Location:Mexico City

Posted Wed Sep 13, 2017 6:07 AM

I would suggest cleaning with alcohol the zone around 3.579545 crystal and also inside the RF module.

Also using the Finger Tester 3000 ™ you pass your finger near the VDP and capacitors to check for floating pins (broken caps mainly)

#5 TPR OFFLINE  

TPR

    Stargunner

  • 1,698 posts
  • Location:Orlando, FL

Posted Wed Sep 13, 2017 8:38 AM

Also using the Finger Tester 3000 ™

 

Been trying to find one of these on eBay.  They seem to go for a *LOT* of money! 



#6 ValkerieSilk OFFLINE  

ValkerieSilk

    Stargunner

  • 1,265 posts
  • Location:Earth

Posted Thu Sep 14, 2017 9:36 PM

I would suggest cleaning with alcohol the zone around 3.579545 crystal and also inside the RF module.

Also using the Finger Tester 3000 ™ you pass your finger near the VDP and capacitors to check for floating pins (broken caps mainly)

The Sausage Finger Tester 4000 ® also works well for this cap test... 



#7 onlyinajeep OFFLINE  

onlyinajeep

    Space Invader

  • Topic Starter
  • 12 posts

Posted Sat Sep 16, 2017 1:29 PM

Deoxited, wiggled, prodded, no luck. Page VIII-1 of service manual: "Vertical lines on background rather than solid blue background with no lines. Replace C106."  New capacitor should arrive next week. I also ordered a new crystal. I have a Rev F1 mainbord, and it appears, on mine anyways, there is a ceramic capacitor bridging C106 on the bottom in addition to the tantalum cap on top(?!?).

 

In this post (link) 'Rex' suggest that the bands are the nature of the Rev F. beast.

 

0916171414.jpg

 

CV Test Cart pattern on Sony Trinitron

0915171347d.jpg


Edited by onlyinajeep, Sat Sep 16, 2017 1:34 PM.


#8 onlyinajeep OFFLINE  

onlyinajeep

    Space Invader

  • Topic Starter
  • 12 posts

Posted Sat Sep 16, 2017 11:41 PM

Success!!! Caps arrived today. Removed both the tantalum and ceramic caps at C106 replace with a new 10uf tantalum cap, vertical bands are gone, so pretty.

 

goofyness in yellow/green artifacts of photography or something...

0917170010.jpg

 

0917170013a.jpg






0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users