Problem Daytona Upright Nanao MS8-26S IC101 Video Amplifier Info

[myPinballs]

Hi,

As titled, looking for info on the little video amplifier pcb used in the Nanao MS8-26S monitor in my Daytona Upright.

I have an intermittent issue where the blue colour disappears (gain goes) and also the blue bias goes high beforehand to. Tried pretty much everything other than this stupid little smd based video amplifier board, so i'm thinking it must be the transistors on this board for the blue section, but i cant find any info on the parts used or a schematic for it.

Does anyone know what the parts used in this little board are? and if there is a schematic for it somewhere? Annoying little board that is mounted vertically to so hard to test

Thanks in advance

Jim

 

[Sbdesign]

When it goes have you tried fiddling with monitor input on the crt?

 

[myPinballs]

Yeah tried everything inc adjusts, cap rebuild, neck transistor change, swapping colour inputs to make sure is a monitor issue which it is.

Need the info on the video amplifier . Why they didn’t include a proper schematic for it is annoying

It’s like the blue amplification just fades away after being on for a minute or so and the bias shows up more for abit to

 

[Ace`]

Sounds like you'll have to reverse engineer it as it doesn't look like anyone else has. LCR-T4 cheap testers are good for identifying unknown parts, especially transistors.

I reproduced a couple of similar konami custom parts using that tester, the hardest part was soldering wires to the tiny transistors and not losing them.

 

[Mykill2.0]

 

[myPinballs]

Thanks but yeah I already have this and it gives no detail. I want a schematic of ic 101 not just a box with ic101 written in it! Lol Nanao you little fuckers!!

Reverse engineer I guess is next option but I don’t have the time right now

 

[Retroman839]

I have just been reading about same issue in game pcb vídeo boards ..

Can you check if you can see any sign some thing has gone open ?

Also look for numbers of smd in a block of maybe 6
2 for each colour ..
bias & gain ..
Three matching circuits ?
One will be bad ..
Then use a resistor 1k
1.5k ohm to look for improvement ..

 

[myPinballs]

I have just been reading about same issue in game pcb vídeo boards ..

Can you check if you can see any sign some thing has gone open ?

Also look for numbers of smd in a block of maybe 6
2 for each colour ..
bias & gain ..
Three matching circuits ?
One will be bad ..
Then use a resistor 1k
1.5k ohm to look for improvement ..

The problem is when it's been off for awhile it works ok for between 5 to 20 mins then eventually goes out. the input signal to the video amp is ok and i can see with a temp gun the blue neck transistors are cold once the colour goes so the signal i think just fades away. Which to me suggests transistors that are dieing as they warm up.

Yes i think the amp circuit is just repeated on this smd board 3 times.

 

[Retroman839]

Cold solder

 

[thegreathopper]

I had pretty much the same fault, sent to Grant who repaired 3 of these chassis for me in a day.

What a guy, highly recommended.

 

[Retroman839]

colour circuit Transistors on neck card common to go bad too ?

 

[Retroman839]

Q451, Q452, Q453 on the MS8-26SG) can cause colour issues, such as one colour disappearing or bleeding.

The above is AI …🫣

Só I thought I would
Look at a schimatic
Ms8 -26sg

Red on neck card goes through Q301 , 302,303& 304

 

[myPinballs]

Q451, Q452, Q453 on the MS8-26SG) can cause colour issues, such as one colour disappearing or bleeding.

The above is AI …🫣

Só I thought I would
Look at a schimatic
Ms8 -26sg

View attachment 44225
Red on neck card goes through Q301 , 302,303& 304

Yeah I already changed the blue set of transistor on the neck pcb

 

[Retroman839]

Bummer ..
I only mention that as nice simple swap .
Grant also fixed both mine 👍

 

[Mykill2.0]

I got something similar going on wit h mne

 

[xga]

The behaviour you're describing sounds very much like a leaky transistor on that IC101 board. Once it warms up after being powered on for a little while, the blue colour fades out. You could use some freeze spray over the transistors on the IC101 board to confirm and identify which one(s) have begun to fail. I'd take a wild guess and say that they are all just standard general purpose SOT-23 NPN transistors like BC817's. As Ace' has suggested, you could remove one of them from the red or green circuit on the board and use a component tester to try identify them.

 

[jasonzob]

I had pretty much the same fault, sent to Grant who repaired 3 of these chassis for me in a day.

What a guy, highly recommended.

Hi there, can you please send me more details about Grant, I have several chassis I need to repair.
thanks !!

 

[thegreathopper]

Actually it was 4 he repaired in less than a couple of days.

This is him here Gunblade aka Grant.