CGL Frogger Repair

[bobmoo79]

So I got a broken CGL Frogger and am hoping to get it running again.

Similar symptoms to the Astro Wars.

No life at all but a power transistor that gets very hot, very fast.

The PCB on this game is great because it provides some part numbers and resistor values. Yay!

I have already confirmed the VFD works.
I have checked all resistor values and they check out.
I have checked all caps for shorts. There are none.
I have checked the 2sc458pc transistor with a DVM and it appears to be fine.

I removed the power transistor (2SC334) and checked it out with the DVM and it gave some peculiar results, but although I'm hopeful that the replacement I have ordered will fix it, I'm slightly skeptical because when I opened it up somebody had already been inside and had drawn a circle in ballpoint pen around this component.

Maybe they identified it could be a problem and didn't replace it, or maybe they DID replace it and it didn't have any effect. I guess I'll know more when the replacement arrives.

As I said most if not all part numbers/values are provided on the PCB so if I need to go and test the diodes then at least I should in most cases know what I'm looking at.

(I still haven't identified the zener diode in the Astro Wars thread. As of 07/05/19)

[Rik]

The most frequent cause of destroying these things is someone plugging in an AC adapter that isn't right for it (too high voltage, or more likely, polarity reversed). This _usually_ fries a transistor and the damage stops there...

Although, with your Astro Wars it seemed that wasn't the case, although the cause of the damage to the machine may have been something else (possible that diode just died...)

That's why I always go for the transistors first. They are easy to test if you want, cheap to just replace if you are too lazy to test them. (And it helps that I have stores local to me that I can just go to and buy components like that off the shelf...) And in all but one case that fixed any broken game I ever had. (That rare case turned out to be the main CPU chip somehow had been fried... I think it was a CGL/Gakken Frogger too, still have the VFD sitting around. )

Good luck with it! Keep us posted.

[bobmoo79]

Thanks Rik, I did order the new transistor straight away but I'm a curious guy so started investigating other options.

In the few minutes that I had spare last night I checked the 13v zener and it's working fine. I don't have a circuit diagram (maybe I'll create one) and I haven't spent that much time looking at the circuit itself but it would make sense this zener regulates the voltage for the microcomputer. I dug out the datasheet and it says it's driven by a voltage of -11v to -13v.

I think in this case if replacing the transistor doesn't work then I'll have a stab at bypassing the power circuit and use my own bench supply to power it to see what happens. This board is much simpler than the Astor Wars one so there isn't really much else to go wrong so I think this approach will confirm the micro is dead.

Anyway, hopefully the new transistor will show up tomorrow or Monday and it'll just spring to life

[bobmoo79]

So that was very simple. Replaced the power transistor and it came back to life.

[mmackin]

Yep, Rik is correct about the power transistor. It's someone trying to play the game and plugging in the wrong polarity or voltage of a power adapter and blowing the transistor. I picked up a broken Fights of the Titan. It was pretty clean, replaced the power transistor and it came back to life.

[OTTOgd]

These posts are a great incentive for me to try and fix my Entex Raise the Devil Pinball, thanks.

[bobmoo79]

If you know how to wield a soldering iron then I'd say go for it.
If it's broken already you can't do much harm by having a go.