[back!] Tempest - Plays blind but tube has glow

[Jodo]

Hi all,

My Tempest is ill!!

Basically after playing 100% fine for 20 minutes last night, the game started resetting itself, gradually resetting faster and faster and by the sounds the cab was emitting the coin counter was clicking up as well with each reset (?) The picture was also flicking on and off with each reset.

Anyway, I dived for the off switch as I didn't want to damage anything.

Now when I power her up the game plays blind. There is power AND neck glow to the WG monitor and that was rebuilt I believe fairly recently.

I've swapped out the AR II for a known good worker - same fault.

I've replaced Big Blue - same fault.

The board is getting a rock solid 5v - measured using the loops on the main PCB.

The X / Y voltage loops on the main PCB measure 1.95v and 2.00v respectively.

I'm thinking if the 5v is good and the monitor has neck glow, then this is a board fault in that after 20 minutes of play something has started to go (hence the resetting) and then finally gone, resulting in no picture tonight.

Any ideas?

Thanks in advance,

Phil.

Jodo2013-06-15 20:14:23

 

[DanP]

Tried putting it into test mode?

 

[Jodo]

Test mode runs through with no sounds produced. No picture but it beeps when Fire, Service and Zapper are pressed. No other sounds....

 

[Jodo]

There is an LED lit on the Deflection PCB: is this the fabled spot killer?

 

[DanP]

That is indeed the spot killer indicator LED. It sounds like it's doing what it's supposed to and stopping (killing) the spot that would otherwise appear in the center of the CRT (quickly burning it). Do you have a scope? If so put it in XY mode and connect up to the X and Y out on the Tempest board to see if you have any vector output. From the self test beeps it sounds like the Program is running correctly.

Dan

 

[guddler]

From your description and symptoms it sounds like the PCB crapped itself and died and you now have a fault with the vector generator part of the PCB.

A little odd that it's playing blind though it usually causes continual resets as you described initially. See what the scope displays first.

 

[Jodo]

Hey guys - I appreciate the feedback - I don't have a scope unfortunately - my technical ability and equipment is limited to a sexy and expensive volt meter which I've used to check the 5v and also taken readings from the X and Y loops.

The reseting starts after around 20 minutes of operation, so when I say it plays blind, yes it does but only for 20 minutes and then it's reset city.

incidentally, I understood that readings taken from the X Y loops during attract mode should fluctuate? Mine don't - they are static at 1.95v and 2.00v.

Is it true that I can plug my Star Wars PCB into the cab to test if the WG monitor is working and hence eliminate that from the list?

 

[guddler]

Not that I'm aware of no. But I'd have to compare PCB pinouts to be 100% sure.

 

[Jodo]

The PCB has now gone off for repair - fingers crossed that's the issue...

 

[Alpha1]

The PCB has now gone off for repair - fingers crossed that's the issue...

sounds like it dude

 

[karlcdoe]

I don't know if the pinouts are close enough on the game boards themselves but if the games are near each other (or you have the extension cable) you would probably get away with plugging the monitor harness from star wars directly to the tempest monitor.

If the spot killer is on you can often (very) slowly turn up the screen control (never taking your eye off the screen whilst you do so) past the point where shutting off the amplifiers is effective which allows one to get a better idea of what is wrong such as missing deflection in one or more quadrants which would indicate an issue with power transistors. Obviously if you overdo it or leave it like that you will burn the tube though. In future it might be worth getting an old cheap 'scope just to use as an xy monitor as it doesn't have to be fast, in fact, even without a z input my positively ancient early 70s EM 102 'scope makes a better monitor than the 'newer' one I have.

Anyway, be interesting to see what happens after you have the boards checked out.

 

[Jodo]

Well that's odd. Mark at Retroclinic has the PCB stack on his test bench and it's booting fine.

Under soak test now.

Even though the tube neck has glow and the spot killer is on, could this in fact be a monitor fault?

 

[Alpha1]

well you should hear the game playing if it was the monitor. Are you sure the game wasn't booting?

 

[Equites]

well you should hear the game playing if it was the monitor. Are you sure the game wasn't booting?

What dude said.

If the PCB was playing blind then it must be the monitor, neck glow just means the CRT heater is working.

If the PCB was not playing blind, then you must have a Power/Edge Connector issue somewhere in your cab.

 

[tb lilley]

I'd keep it simple. The one thing you now know is that there's no fault on the PCB, so that's fine. You said the board was resetting in your cab. Suspect that might be related to a power issue. As you've already tried a known working AR2 I'd look a bit earlier on in the power chain. Check and clean fuses, fuse holders. Maybe test / replace bridge rectifier on the power brick. Check connectors etc. I know you said you had a solid +5, but you only know it was solid for the period of time you were checking it for.

If, when you get the PCB back, you still get no picture on the monitor, again, keep it simple. Have you checked fuses on the chassis? May be a case of a power issue that was causing resets / problems with the PCB. Then, on top, you've now got a seperate issue with the monitor. Don't know enough about WG6100s, but I wonder if the PCB was throwing a load of crap at the monitor and that's caused something to let go.

 

[edwoodjnr]

Check you are getting 181v from the HV unit (pin 5) and also check the other connector with the 2 wires on the HV unit. I recently had both a Tempest and Star Wars with one of the 2 wires from the HV unit that came loose giving me no picture.

 

[Jodo]

Hi all,

The game was booting and playing blind but started resetting once it had warmed up. The monitor 'clicked' with each reset until it just didn't come at all. The PCB still booted; I could not determine if it was still resetting though as by that point I had no picture.

Mark has had the board on soak test and also replaced the interconnnects and it did not reset once for him and gave good geometry etc.

I've checked the fuses on the power brick and all are good.

I will need to take the screen back out and check the fuses on the monitor board.

One thing I did notice before the screen crapped out was an 'acidic' smell coming from the cab; I'm betting the resetting issue has blown something on the 6100. I am browsing for a rebuild kit as I type this....

When you say "Check you are getting 181v from the HV unit (pin 5) and also check the other connector with the 2 wires on the HV unit. I recently had both a Tempest and Star Wars with one of the 2 wires from the HV unit that" what am I looking at here - the wiring block that goes into the back of the WG?

 

[Alpha1]

Fit an LV1000 if you haven't already too. I would also:

1. Do the 'sense' mod on the ARII

2. Ensure you have a good brick - check big blue

3. Check your edge connector on the loom - make sure it's still good - clean the contacts and check for any burning and replace if necessary.

 

[karlcdoe]

Like I suggested before crank the screen brightness up very carefully and see if a partial screen is being drawn, if so and you are sure the gameboard works then it's the monitor or a wiring fault. For what it's worth I've been working on quite a few SW boards recently and I had bad contacts between the power brick and the loom to the AR2 that was causing the +5v to drop out and stop the game in its tracks. Either that or find a way of making the cables long enough to plug your monitor into your SW to see if you get a picture,

Incidentally, I wouldn't worry about the big blue or sense mod at this stage since there are conflicting arguments, also Mark Spaeth (who I would say knows what he is doing) implies its a futile exercise if you see here http://cambridgearcade.dyndns.org/?q=node/76 either way as long as the edge connectors are good enough I'd just clean with an eraser and check you have a solid voltages (esp +5v) at this stage. If the voltages are duff, especially under load then I'd work backwards from the edge connector -> AR2 -> power brick for that line (use a dummy load rather than a decent PCB - or you could hang a street fighter off the +5 line . I usually just replace the 2N3055 if I have the AR2 out as its a fairly commonly available part. but... I wouldn't do any of that for the minute unless I had an obvious power issue.

......In fact you said you had solid voltages in your original post, you'd replaced the big blue and the AR2 so unless something has changed it looks very likely to be the monitor. Could be one or more of the TO-3 transistors or dodgy contacts on where they plug in. I'd say if you are not averse to fiddling with your star wars and the inherent risk of disturbing the connectors on it then as the monitor is plug and play you would be best to trying tempest on the SW monitor or vice versa.

 

[Equites]

I'm not a fan of the Sense mod either, much better to fix the underlying problem which is usually a poor edge connector (what do you expect after 30 years?).