Tempest Assistance needed

I ordered a flyback because everything else checks out. I suspect the flyback anyways.


When you say 'checks out', explain exactly how you are testing everything.

Anything is possible, but I've literally only ever seen 5 or 6 bad 6100 flybacks (in hundreds of rebuilds), and in all cases they were visibly melted on one side, usually the side closest to the focus block.
 
The HV cage I just rebuilt had a bad 55 timer. I kept suspecting the transformer, but a search on here will show you that a resistance of around 18 ohms on the primary is right.
 
When you say 'checks out', explain exactly how you are testing everything.

Anything is possible, but I've literally only ever seen 5 or 6 bad 6100 flybacks (in hundreds of rebuilds), and in all cases they were visibly melted on one side, usually the side closest to the focus block.

I have measured resistance on every resistor.
Replaced all electrolytic caps, and triple checked orentation. Removed all ceramic and mylar caps to check capacitance.
Replaced Q901/902 with MPS A06. Replaced Q903. Checked the remaining Transistors with normal transistor testing procedures. The case transistor is not shorted to the cage.
Replaced T901.
checked every diode. Replaced D901 and D902
Preset the Potentiometer to 5.5K
I replaced the 555 timer, then grounded my positive lead, placed the meter on Diode test, and independently checked each leg with the negative lead. All pins are .5-.7 volts, except pin 1 which is on the B- plane, so I'm not worried about it.

I removed the flyback and here are the measurements.
3-6 = .8 ohms
6-9 = .8 ohms
3-9 = 1 ohm
I thought this was normal so I'm not sure where to measure in order to get 18 ohms.

I also installed fuses in line with R901/907/917. The one at R901 blew along with the smoked R912.

I have reflowed the connections.

I feel like I have been completely through this but it is possible I have missed something. Right now I am just going to wait on the flyback.
 
I have measured resistance on every resistor.
Replaced all electrolytic caps, and triple checked orentation. Removed all ceramic and mylar caps to check capacitance.
Replaced Q901/902 with MPS A06. Replaced Q903. Checked the remaining Transistors with normal transistor testing procedures. The case transistor is not shorted to the cage.
Replaced T901.
checked every diode. Replaced D901 and D902
Preset the Potentiometer to 5.5K
I replaced the 555 timer, then grounded my positive lead, placed the meter on Diode test, and independently checked each leg with the negative lead. All pins are .5-.7 volts, except pin 1 which is on the B- plane, so I'm not worried about it.

I removed the flyback and here are the measurements.
3-6 = .8 ohms
6-9 = .8 ohms
3-9 = 1 ohm
I thought this was normal so I'm not sure where to measure in order to get 18 ohms.

I also installed fuses in line with R901/907/917. The one at R901 blew along with the smoked R912.

I have reflowed the connections.

I feel like I have been completely through this but it is possible I have missed something. Right now I am just going to wait on the flyback.




Two things:

- What does 'normal transistor testing procedures' mean? You mention checking for case shorted to frame, but that does not completely test the transistor, and it does not cover the non-frame-mounted transistors. You need to do a full test using the diode test method, to and from all 3 pins.

- You also didn't mention the Zener diodes. These are common failures, and cannot be tested with a DMM. (You can test them like regular diodes, but that does not test the Zener function, so it's best to just replace them.) There are either 3 or 4 of them, depending on what version of the cage you have.
 
Two things:

- What does 'normal transistor testing procedures' mean? You mention checking for case shorted to frame, but that does not completely test the transistor, and it does not cover the non-frame-mounted transistors. You need to do a full test using the diode test method, to and from all 3 pins.

- You also didn't mention the Zener diodes. These are common failures, and cannot be tested with a DMM. (You can test them like regular diodes, but that does not test the Zener function, so it's best to just replace them.) There are either 3 or 4 of them, depending on what version of the cage you have.

For testing the transistors using the diode test method, I have placed the negative lead on the Emitter, positive on the Collector, then Base. Then move the negative lead to the base, and check collector and emitter. Flip the leads and so on. So that is what I mean by normal transistor testing. I understand NPN and PNP and how to test transistors.

As far as the Zener's, I may have some around here. I will look. I did do the normal diode test on them, but if it's best to replace them I will. I will look up the part numbers and see what I have.

The HV is P316
 
For testing the transistors using the diode test method, I have placed the negative lead on the Emitter, positive on the Collector, then Base. Then move the negative lead to the base, and check collector and emitter. Flip the leads and so on. So that is what I mean by normal transistor testing. I understand NPN and PNP and how to test transistors.

As far as the Zener's, I may have some around here. I will look. I did do the normal diode test on them, but if it's best to replace them I will. I will look up the part numbers and see what I have.

The HV is P316


For a P316, there are three Zeners. Two 13V 1W and one 150V 3W. Be careful not to mix up the D90x and ZD90x locations on the board, as they are obviously not the same.

My guess is that's most likely your issue.
 
It looks like ZD902 is a 4764, which I have and already replaced.
ZD900/901 are 4743's which is doesn't look like I have.
 
Thanks for your help AndrewB. I am just going to wait on parts to arrive then report back. Give it a week or so.
Thanks!
 
Two nine volt batteries will give you enough voltage to test out those 13V zener diodes.
 
Two nine volt batteries will give you enough voltage to test out those 13V zener diodes.

That's interesting. I've never done that. How exactly do you do that. I have a very robust adjustable 30volt DC power supply I can test with.

Also, I have read about using a high voltage probe to adjust the HV. Not sure my meter can measure that high, so in addition to having a HV probe what type of meter do people use?
 
Zeners test good!
Connected a 100 ohm resistor to cathode of the zener, then positive side of a 15 volt DC supply to the other lead of the resistor. (resistor and diode in series with the anode on ground). Then connected the negative side of the power supply to the anode of the zener. I did this with both 13 volt zener's independently and measured 13.3 volts taken across the zener.

ZD902, 150volt, was replaced with a 5 watt version.

I still have smoke on R912.

So here is what I think.

I replaced D901 and D902 with a MUR2100EG according to parts list I came across. According to the 6100 FAQ's these two should be a NTE 558 (or 1N4948 from what I was able to cross reference). The MUR2100 EG is a 1,000 volt 2 Amp fast switching diode. The NTE 558 is a 1,500 volt 1 amp fast switching diode. Is that my problem?
 
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I use the MUR2100EG's with no issues.

For the HV probe, the Fluke 80k-40's can be used with any 10 Megohm DMM. I have a cheap Chinese one that works fine.
 
OMG! Color me embarrassed! My eyes are not what they used to be. I misread R928 for R926 on the HV board!! That means I put a 2.2 ohm 2 Watt resistor, where a 56K 1 Watt should go. No wonder 912 was smoking.

So I got that fixed and I have life now!!!

The problem is there are some monitor adjustments that I can't seem to get in.
#1 the X image is reversed. (I did not do anything to the wires)
#2 the X size wont adjust any smaller.

I'm beginning the next phase of troubleshooting. After the rookie (believe me I'm not a rookie) mistake with the resistor, I am not afraid to say there is likely something I overlooked.

B+ is at 181VDC.
 

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Don't run your monitor for too long with that supersized image or things will get cooked! Suspect a broken leg on one of the adjustment pots, a bad 1495 at C12, or bad scaling circuitry. Check self-test screen #4.

Make sure your harness has good connection between pins J and 15, and between pins K and S. Those jumpers allow Tempest to control its own X and Y flip.

It does so by way of the LS174 at N9. If your coin counters are also not working, suspect that chip or the BB* signal that clocks it (which comes from one of the address decoder chips J5).
 
A flipped image can be due to a bad Pokey (in addition to other things). Put the game into test mode, run the self test, and see what it reports. See the manual for details. Or post a pic.
 
Don't run your monitor for too long with that supersized image or things will get cooked! Suspect a broken leg on one of the adjustment pots, a bad 1495 at C12, or bad scaling circuitry. Check self-test screen #4.

Make sure your harness has good connection between pins J and 15, and between pins K and S. Those jumpers allow Tempest to control its own X and Y flip.

It does so by way of the LS174 at N9. If your coin counters are also not working, suspect that chip or the BB* signal that clocks it (which comes from one of the address decoder chips J5).

pots are good, I looked at them and tested. Connections J-15 and K-S are good. I will be looking at this further tomorrow night.

Thanks Guys!
 
You may also have a bad 13201 switch chip in the analog section (which is one of the chips involved in the image-flipping circuit). You may also have a bad amp, or a broken resistor or cap in the area around those chips.

Look very closely at all of the components in that lower silver corner of the board where the pots are, and make sure no resistors or caps are broken or missing (in addition to running the self-tests per above).
 
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