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data east dmd ***FIXED***
- Thread starter deathrow
- Start date
OP
OP
Done some PSU testing and I have a couple of issues.
Banded side of d5 according to pinwiki should be +68v I have +163v!!
I took all new caps off and checked all traces on the pcb for shorting. Nothing. I checked the caps and they seem to be fine. I even popped the old caps at C10 and C11 back on and still gives the same reading. Surely its not the new transistor I bought at TR3 is it?
Comes from a reputable supplier but I cant find any other reason for the fault other than this.
I cannot change the transistor back at TR3 as this was binned.
Help?
Banded side of d5 according to pinwiki should be +68v I have +163v!!
I took all new caps off and checked all traces on the pcb for shorting. Nothing. I checked the caps and they seem to be fine. I even popped the old caps at C10 and C11 back on and still gives the same reading. Surely its not the new transistor I bought at TR3 is it?
Comes from a reputable supplier but I cant find any other reason for the fault other than this.
I cannot change the transistor back at TR3 as this was binned.
Help?
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Not familiar with the circuit off the top of my head, but yeah, if you have that high a voltage on the output, it has got to be a shorted transistor or regulator (definitely no shorted tracks?)
OP
OP
Thanks Moonraker
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OP
OP
Deff not shorted tracks. I have triple checked due to the board repairs. Even pulled things off the board again to get a real good check with the multimeter. All is ok.
OP
OP
MJE15030 on order just in case.
Going to look at all components of 68v section...
Going to look at all components of 68v section...
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OP
OP
Pin wiki...
Measurements are with respect to ground. You should now have a HV +DC reading at the banded side of D5. Test for +68v output. You should also have a HV -DC reading at the non-banded side of D7. Test for -100v and -98v DC output.
Do not be concerned if measured voltages are not exact without a DMD connected, they will read lower under load. It can also be that the DMD display itself is faulty and taking down the PSU.
Capacitors C10 / C11 are important, if you can't test then replace them. Especially if it looks to bulge at ends, old capacitors dry out and then fail. C10 and C11 are both 100uF @ 200v. You should be able to use 150uF at a higher voltage for these, so 150uF @250v is fine.
D5 / C10 are for the +68v HV DC to the DMD Display. D7 / C11 are for the -98v and -110v HV DC to the DMD Display.
As you can see I have followed this and got nothing of the sort.
I unplugged the dmd and tested the pins at CN5, results are interesting.
1, e
2 -101.8
3, -113.9
4, +60v
5, +11.8
6, +4.9
7, -
Pin 4 is low. this should be 68v +/- 10%. I don't have a dmd connected.
Dont know what to think now lol
Measurements are with respect to ground. You should now have a HV +DC reading at the banded side of D5. Test for +68v output. You should also have a HV -DC reading at the non-banded side of D7. Test for -100v and -98v DC output.
Do not be concerned if measured voltages are not exact without a DMD connected, they will read lower under load. It can also be that the DMD display itself is faulty and taking down the PSU.
Capacitors C10 / C11 are important, if you can't test then replace them. Especially if it looks to bulge at ends, old capacitors dry out and then fail. C10 and C11 are both 100uF @ 200v. You should be able to use 150uF at a higher voltage for these, so 150uF @250v is fine.
D5 / C10 are for the +68v HV DC to the DMD Display. D7 / C11 are for the -98v and -110v HV DC to the DMD Display.
As you can see I have followed this and got nothing of the sort.
I unplugged the dmd and tested the pins at CN5, results are interesting.
1, e
2 -101.8
3, -113.9
4, +60v
5, +11.8
6, +4.9
7, -
Pin 4 is low. this should be 68v +/- 10%. I don't have a dmd connected.
Dont know what to think now lol
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OP
OP
Done some digging on t'net and have found a repair guide thats looking just like my issue...
http://techniek.flipperwinkel.nl/desega/index3.htm
"A very common problem on the small 16x132 displays (as used on five games, Checkpoint to Batman) is a failed R95 resistor. It is very common for this 33k, 1/2 watt resistor to go out of spec, or even open. This will cause the display to look garbled (see picture). Often the display itself is fine; it's just this resistor that needs to be replaced."
Off to see where I can dig me up one of those
http://techniek.flipperwinkel.nl/desega/index3.htm
"A very common problem on the small 16x132 displays (as used on five games, Checkpoint to Batman) is a failed R95 resistor. It is very common for this 33k, 1/2 watt resistor to go out of spec, or even open. This will cause the display to look garbled (see picture). Often the display itself is fine; it's just this resistor that needs to be replaced."
Off to see where I can dig me up one of those
OP
OP
Got hold of a resistor from maplins, fitted and no difference.
Its got to the be the low 68v. 60 is just too low.
That rottendog is getting mighty tempting!
Its got to the be the low 68v. 60 is just too low.
That rottendog is getting mighty tempting!
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OP
OP
any guesses on how to up the 60v?
Help
Help
- Joined
- Jul 21, 2011
- Messages
- 2,468
The 68v is set by a Zener diode. Don't have diagram to hand. It's worth switching your meter to AC and measure the 68v again. If you have large AC you have a problem elsewhere. If it's low then try replacing the Zener.
- Joined
- Jul 21, 2011
- Messages
- 2,468
What happened to the 163v you had?
OP
OP
Done some PSU testing and I have a couple of issues.
Banded side of d5 according to pinwiki should be +68v I have +163v!!
I took all new caps off and checked all traces on the pcb for shorting. Nothing. I checked the caps and they seem to be fine. I even popped the old caps at C10 and C11 back on and still gives the same reading. Surely its not the new transistor I bought at TR3 is it?
Comes from a reputable supplier but I cant find any other reason for the fault other than this.
I cannot change the transistor back at TR3 as this was binned.
Help?
I still have the 163 at d5.
Pinwiki was a little misleading. I read it as a measurement point at the banded side of D5. I think you are just supposed to look for HV at D5 if the 68v is missing at the pin or DMD.
Im going to rebuild the 68v section. Including the zener.
Can you help with these parts in your shop?
+68v circuit
MJE340†NPN transistor TR3 Sourced
MPSA92PNP transistor TR1 Required
1n4760B68v zener diode D9 Required
1n52283.9v zener diode D6 Required
1n4004diode 400v @ 1A D5 Sourced
47Kresistor 1 Watt R8 Required
330Kresistor 0.5 (1/2) Watt R11 Required
1.5Kresistor 0.5 (1/2) Watt R12 Required
500 ohmresistor 10 Watt Ceramic R15 Required
100uF @200vCapacitor C10 Sourced
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OP
OP
Ok, I now have a dmd 68v thats within tolerance. at 65v. (68 +/- 10%)
Replaced TR3 and 68v D9. psu now lurvelly
So what do I have? A nice and very bright but completely garbled dmd lol
Is there anyone I can post my dmd to that would be willing to try it in a working machine please? (beer token sent to anyone who can help me get this sorted)
Anyone on here have the power to produce a set of roms for me?
Going to replace the display rom so may as well have a full set.
Replaced TR3 and 68v D9. psu now lurvelly
So what do I have? A nice and very bright but completely garbled dmd lol
Is there anyone I can post my dmd to that would be willing to try it in a working machine please? (beer token sent to anyone who can help me get this sorted)
Anyone on here have the power to produce a set of roms for me?
Going to replace the display rom so may as well have a full set.
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OP
OP
The dmd never got the 163v. It was getting a low 68v at just 60v.
I have read that the low voltage can effect the roms so Im going to look at that too.
I will however check R95 again as this was a metal film resistor from Maplins. How good they are is questionable.
OP
OP
Gone back and checked R95 and found it open.
Took it off the board and checked it..
Now with it being a sunday I Pikey'd it and pulled a 33k from an old Bally board.
AND.......
So @Moonraker you have saved me from buying a replacement and wasting money. Please PM me your PP so I can send you a couple of beer tokens!
OP
OP
To you guys searching this issue on a well known G search engine and found yourself here....
Check and re check R95 on the data east small DMD.
Get a decent quality resistor as a replacement. Don't go cheap!
Re-folow the power connector pins and the Ribbon pins. (easily done without removal of the glass)
If this thread helps you fix this issue then please donate a small thanks to the site!
Check and re check R95 on the data east small DMD.
Get a decent quality resistor as a replacement. Don't go cheap!
Re-folow the power connector pins and the Ribbon pins. (easily done without removal of the glass)
If this thread helps you fix this issue then please donate a small thanks to the site!
Got my Hook set up there, dmd works fine but I have a problem where it's blowing a fuse.
Guess you don't need to send you dmd over now, happy days.
Guess you don't need to send you dmd over now, happy days.
OP
OP
I'm all sorted now thanks.
what fuse is blowing?
what fuse is blowing?
Nice work all. And that's why this forum is great
Not in front of it at the moment but I think it's the bottom one on the power supply board .. F5 is it ?
I will double check when I get home, causes no flipper or eject to plunger etc left my multimeter in work so will check high voltages tomorrow
Great to know it's fixed, nice one.
OP
OP
If you need me to check/match values etc when you take some readings just let me know.
OP
OP
Another pearl of wisdom from @Moonraker! Top blokeSo @Moonraker you have saved me from buying a replacement and wasting money. Please PM me your PP so I can send you a couple of beer tokens!
Shame you aren't closer to Salisbury, @deathrow, else you could pop into http://www.specialwhenlit.co.uk/ and thank Peter in person
OP
OP
I live in farmer country in no-where land. would love to visit though
Hi all, thought I would ask on this thread rather than start a new one, display went out on my hook today, checking voltages at CN5 pin 4 (+68v) has only got +20v , no AC voltage, am I likely looking at a diode, if so which, is it D5?
Thanks, Andy
Thanks, Andy
OP
OP
Sounds like the 68v Zener, Mine went bad too.
