Sanwa PM1745C Flyback "coil" dead?

[capsule]

Hi,

I'm in a process on MAMizing a Virtua Striker 2 cab.
I've bought a complete but not working one.

Changed the 4A fuse in the power supply, plugged it and... The PCB turns on but the monitor (29" with a Sanwa PM1745C chassis) didn't turn on. Maybe it did a bit.. I've seen like a flash of light inside the cab.

I checked the chassis and saw a broken kind of coil next to the flyback. I guess that's what was fried when pluging it (or maybe it was already dead...).

What is it? Is it easy to change and are they possible other damages? Would you try to repair this or buy a new replacement chassis?

Thanks for any info!

[ed12]

hi
that is a horz tunning coil
should olny have 2 lead's to it ?
if so and 1 is broke,u can jump the coil out to test the chassic,
and by test i mean run it long enough to see a pic.,then turn if off and fix the coil
if not then u have other problem's

ed

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Thanks Ed, I will do that and keep you posted!

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OK, I've taken the chassis out and accessed the damaged coil.

It's the L404 (marked "C7641") coil. Indeed 2 leads only.
The resistor next to it (R315) looks damaged too (or maybe this resistor broke the L404 when frying).  Do you know its value? I've read 4.5 ohm when measuring unsoldered but I guess it's not accurate.

F802 (1.5A 125V) fuse is also blown.

I have to buy this kind of fuse, I've only got 4A 250V ones and I don't want to try with a bigger one in this situation :-)
Knowing the R315 value would really help so I can't find a replacement one.

Thanks!

[capsule]

I've taken R315 out and it reads Red White Gold Gold so I assume it's 2,9 ohm.
It still reads 4,5 ohm when measuring, that's far beyond the 5% tolerance and confirms it's fried as well.

[ed12]

hi
red white gold gold
.29 ohm
if ohm's law has not failed me
normally used as a fuse to a secondary circuit off of the flyback
chk heater's/vert out ic or circuit
neck board cap,etc etc
the coil u can repair

ed

[capsule]

Gold is 0.1x so 29x0.1 = 2.9 ohm. But it might be orange and not red, hard to tell on old dusty resistors.

Orange White Gold would be 3.9 ohm.

There are other resistors with the same color code around the flyback (R129 and R130). They look sane and read 4.5. The fault tolerance says +/- 5%, which would mean around 4.1 so that's close to 4.5, maybe they get a bit more resistant when aging.

So, after all, I don't think the resistor is bad, it might have suffered a bit but still functional.

But would you by any chance have this very same chassis to check the real color code?

I've managed to repair the coil, yes. I've got like 3 ohm of resistance so I guess there's no shortcut. Hard to test a coil but from my experience with pinballs, Good coil have a small resistance.

Q804 is also fried and I've seen a few of the Q801 to Q806 serie has been changed already. I guess the Power part of that chassis has suffered in the past and I will change all this serie of transistors.

R808 and R805 look darkish too, I will change them (I've got them values from another forum's old thread about someone repairing the same chassis).

From what I see, there's no blown caps and the neck board look OK too.

I will get the necessary fuse, transistors and resistors and will replace as much as I can to be sure.

Thanks for the help!

[capsule]

OK, I received the needed parts and changed a bunch of transistors/resistors :

Q802
Q803
Q804
Q805
R805
R808
R811
R817

Plugged it again. R817 and F802 blown.

I'm a bit lost now, what should I check?

Thanks!