sega frankinstein

[positive logic]

A friend of mine has just bought one of these and although it mostly works ok it does have a fault.
There is a display screen on the top box which flickers on and off and my friend has checked the connections to the circuit board that the display is mounted on and this has made no improvement to the problem.
He did mention there is a hum on the sound and we wonder if this is related to the above fault.
This pintable was made in 1990.
Both my friend and i can repair a circuit board.
Any help would be much appreciated.

Robin

 

[Funhouse71]

Found this Sega service bulletin regarding the matrix display cutting out intermittently

https://arcarc.xmission.com/Pinball/Stern Service Bulletins/sb/sb106.pdf

 

[positive logic]

Found this Sega service bulletin regarding the matrix display cutting out intermittently

https://arcarc.xmission.com/Pinball/Stern Service Bulletins/sb/sb106.pdf

Thank you for your reply funhouse71

 

[Ronnie Dent]

You can power the display with a standard pc psu it's plug and play to check if it's a power issue

 

[athena]

Sega Frankenstein has a XL DMD the same as maverick, baywatch and Batman forecer. They are notorious for failing. They are running on high voltage and approx 25 years old so nowadays you need to check voltages to make sure it’s getting 5v

Power driver board voltage regulator would be first thing to check and all the connections. Cold joints on pins is normally the culprit and once you sort out the power supply board (top left in backbox) it should resolve issue.

The dmd could be on its way out but it sounds very much like a voltage issue because display is working intermittently.

I recently had all 4 and so far they all needed work on power supply board. My guess is dry joint. 5v regulator definitely worth changing if your pulling the board out.

 

[positive logic]

Sega Frankenstein has a XL DMD the same as maverick, baywatch and Batman forecer. They are notorious for failing. They are running on high voltage and approx 25 years old so nowadays you need to check voltages to make sure it’s getting 5v

Power driver board voltage regulator would be first thing to check and all the connections. Cold joints on pins is normally the culprit and once you sort out the power supply board (top left in backbox) it should resolve issue.

The dmd could be on its way out but it sounds very much like a voltage issue because display is working intermittently.

I recently had all 4 and so far they all needed work on power supply board. My guess is dry joint. 5v regulator definitely worth changing if your pulling the board out.

 

[positive logic]

Thank you guys for your input and here is an update on this pintable.
All connections have been checked and the display board has been run from an independent 5v supply.
This made no difference to the fault condition but the independent 5v supply was only connected to the top pcb of the display board assembly and not the pcb that the glass display panel is attached to.
Do we also need to supply this pcb with the independent 5v supply ?
I notice this pcb attached to the glass display has quite a few electrolytic capacitors , are these troublesome ?
The pintable,s own power supply was supplying 4.98v to the display .
The display is very intermittent to the point that it will flash something about once every 20 seconds.

 

[athena]

The problem sounds like it lies within the main power supply board which is what I said in my first reply to your post.

This board produces the voltage for the display and the machine. The regulator fails all the time and they are literally pennies to buy and easy to replace. This would be the first thing to try.

By supplying it seperately you aren’t supplying the high voltage side of it. The seperate power supply is now only powering the cpu. So it won’t be Helping the display and graphics card.

The 4.98 v sounds borderline but that will vary during gameplay when the machines load changes, hence the regulator.

Service or replace the power supply board and I think you might rectify the issue. I’ve had these issue on these specific sega games. I can’t advise anything else at this stage.

 

[positive logic]

The problem sounds like it lies within the main power supply board which is what I said in my first reply to your post.

This board produces the voltage for the display and the machine. The regulator fails all the time and they are literally pennies to buy and easy to replace. This would be the first thing to try.

By supplying it seperately you aren’t supplying the high voltage side of it. The seperate power supply is now only powering the cpu. So it won’t be Helping the display and graphics card.

The 4.98 v sounds borderline but that will vary during gameplay when the machines load changes, hence the regulator.

Service or replace the power supply board and I think you might rectify the issue. I’ve had these issue on these specific sega games. I can’t advise anything else at this stage.

Thank you Athena , i will tell my friend to buy a new regulator and report back.

 

[athena]

Thank you Athena , i will tell my friend to buy a new regulator and report back.

I hope it sorts issue. Definitely first thing to try and if it sorts it, it’s cheap and easy

 

[positive logic]

Ok reporting back on this pinball.
A new 2N6056 regulator was purchased and fitted which rased the 5v line from 4.98v to 5.04v but the fault is still the same.
Does this mean my friend needs a replacement display board ?

 

[athena]

Tbh it’s almost impossible to diagnose the fault over messages, it could be lots of things it still sounds like a dry joint to me some where. The next logical step would be to check what voltage you have at the display driver board to see if they are close to the manufacturer recommend values. Buying a replacement display is an expensive move if that doesn’t remedy the issue. If it’s a dry joint it’s simple to fix and costs nothing but you need to find it.