Analogue monitor board repair

tony duell ard at
Mon Oct 31 14:51:09 CDT 2016

> My recent Executel addition has a 5" screen with associated analogue board
> that seems to be powered from a display chip I can't find any info on, and

Well, it won't be _powered_ from that IC. My guess is that said IC provides
the HSync and VSync signals, the video comes from other devices on the
main PCB. But that is a guess without seeing the machine/


> I've also removed, checked and replaced out of spec capacitors, one of them
> was a 680nF 50V radial. I could only find a 63V PET version on cpc's website
> and did much reading on differing capacitor types, concluding that it SHOULD
> be OK.

I would be very surprised if that was not OK.


> Hence the question - am I wasting my time without a schematic for this
> analogue board?

You haven't told us what the problem is.

Do you get anything on the screen? Is the CRT heater glowing? Have you
measured the CRT pin voltages?

I can see one IC on that 'analogue board'. Looks to have metal heatsink 
tabs so I am going to make a wild guess that it's a TDA1170 vertical 
deflection IC Are there any other ICs on the board? My guess is that
the 'analogue board' could be reverse-engineered without too much

Can you provide a clear picture of the component side of the
board with nothing else in the way?


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