Vector Problems Battlezone , Experts here?

[Danschki]

Hello Folks!

for some time now i have had the problem with my Battlezone that when i switch on the machine when it is cold, the complete picture is not displayed. only after 20 minutes is the picture almost 100% available.
I thought that the capacitors needed to be changed, they were all replaced, same problem.
I'm a bit at a loss as to what the cause might be.
i hope i can solve the problem with your help

Coldstart Battlezone

After 15 Minutes

Testmode


cheers and many thanks
Daniel

 

[Mitchell Gant]

Looks like it could be the Y axis "window" blanking circuit that has a failing component when cold.

Could be op amp TL084 at C11, comparator LM319 at D12 or analogue switch LF13201 at D11. Or even diodes CR3,4,5 or 6.

That's my guess anyway!

 

[Mitchell Gant]

If you have some freezer spray you could wait until its warmed up and got full image, then spray each of those chips in turn, wait a few seconds and see if the image blanks out again.

Can of freezer probably costs more than all those chips though...

 

[Danschki]

Thanks a lot, i will try it.

 

[Danschki]

hello guys!

wanted to report back here briefly. was a bit sceptical, only knew it the other way round, when a component gets warm, that it causes problems. that a component only works properly when it gets warm was new to me.
I tried the cold spray and it worked. D11 is the culprit, when it is sprayed with cooling spray, the image degrades again.
thanks a lot Mitchell Gant, I'll get a chip like that now and then report back whether it really was the fault.
cheers
Daniel

 

[Danschki]

Hi Folks!
It's done, i change the IC with the equivalent DG201BDJ .
Now the graphics are back 100% from start.
Cheer and thanks for help