Sys. 80 So far I have cleaned all the edge connectors. Did the ground mods according to John's Jukes. Replaced coil diode. Changed out big orange cap. Rebuilt power supply. The fuse will blow after the game has been on for 15 to minutes, even when pop is inactive. I did notice that the fuse wasn't a little loose in the clips so I squeezed the clips to tighten up the fuse.

Are the connector pins for the driver board still available? I'm also wondering if somebody reversed the wires at the coil since it's apparent that the coil was changed. This game has been HUO since the late 80's.

IIRC F11 for the main pf lower left pop. Not as often but the fuse for the cellar pf pop bumper also blows. F-8. According to John's Jukes site, he said to check the connectors pin 9 and 18 A1J6 and they do look discolored, they supply 5 volts to the PBDB's but I'm thinking it might be a power problem and not logic. I have been working on this game occasionally for about a year. Back then, I bought a repro pop bumper driver from Pioneer. The fuse was still blowing with that board installed. It also has a weird issue causing the pop bumper to fire when the left flipper is activated. So back in with the original. I think I even swapped them around to test them.

So can I use the Bifurcated pins in the black edge connector? The originals are not Bifurcated.

Yes, the resistance was consistent with a new coil. So I need Molex .156 connector pins for the A1J6?
I just took a hard look at the schematics. I'm thinking the coil wires might be reversed going by memory from changing the coil diode today. I know the owner's dad did some work on the game. The solder job is very ameture looking. I hope I'm wrong though because I'm sure that would have caused some damage.

Yes the main pf lower pop blows very consistently. F-11 under the pf. It's been a while but I think I did swap the PBDB around and the same fuse blew again. Then again, I also have F-8 blowing so I could have 2 bad boards.

No my game is blowing F11 for the main pf lower left pop. F4 should be coil voltage for the whole game. Have you done the ground mods?

Ouch! That's a big glass too! It's odd that a PBDB is taking out the main fuse, I thought each pop has their own fuse? Is it possible that somebody over fused the pops? I would double check the fuse values. Do all the pops lock on at start up? If all pops are locking at once, I guess it is possible to pull enough current to blow F4.

Yeah that's true, very hard backglass to find. The ground mods are easy to do. Atleast do the jumpers from the power supply, MPU and driver board to the frame of the power supply board. Also change the orange cap in the cabinet if you suspect it's original.

https://www.flippers.com/gottlieb_ground_cures.html

Yeah I was just looking at that site. The game is at a friend's house so I can't look right now. I'll report back once I can get at the game.

I was able to verify that the coil is wired correctly via the schematic. I was also able to verify that the PBDB's are the non-modified versions. I'm still confused about why the repro driver board activates the pop bumper when the left flipper is activated.

I replaced the diode on the coil with a new 1N4004. That was the first thing I thought of that might cause the fuse to blow, no dice. the leave switch looks fine, as does the scoring switch. Could it be a bad diode on the flipper coil causing the repro board to activate the pop bumper, it does it on every hit.

Ordered parts from GPE to modify the drivers. Also ordered new transistors Q1 from ebay. Also has anyone ever needed to change the fuse clips out? Maybe they have tarnish build up of overheated plating?

I saw the TIP-102 thing on Pinwiki. I found these made by Motorola and US seller so I thought I was in the clear as far as fakes, any way to tell? They will delivered tomorrow.

ebay.com link: itm

It only happens with the repro board, it must be faulty or poor design?

Yep, looks like these are fake. I read Terry's page on fakes and he explained that the Motorola ceased production in July of 2000, so any date marked later than that are fake. It looks like mine have had the date code removed evident by hairline scuffs, possible from fine sand paper. He explained that the counterfeiters are getting smart, so this guy must have removed the date code. Also the mounting plate is stamped with numbers and letters by the ears, CJ on one end and 927 on the other. Don't know what that means. Tough lesson learned!

Is there a suitable replacement in the T0-3 case?

Ed, not Terry, Doh!

I went to my friend's house today and pulled the PBDB's from the game. It turns out that 2 of them were updated and 2 not. The one that's driving the pop that keeps blowing the fuse had an unmodified board.
This is what I found today,F11 for the main pf lower pop blows very frequently, this is driver A84, usually after the game is on for 10 or so minutes. That one has the unmodified board. That pop is on the 38V circuit. Then F-13 blows, not as quickly, for the lower pf pop (A83), also had a unmodified driver driver, 24V circuit. But with the new repro driver connected to A84, the fuse still blows and has the weird flipper issue. See pic, does anyone have one of these in their game? These drivers sell for around $20 so I figure they are cheaply made. So I'm not sure if modifying the drivers will fix my issue.

P6180030 (resized).JPG

I wrote to the mfr of the board and explained the problem, will post what they say.

Parts on the way for the mods. It won't hurt to do them and not expensive either. The 2 other drivers that are modified are date stamped 9/83. The game has been HUO since 89 so it must have had issues early in it's life to receive at least 2 modified boards. The bad thing is that the game wasn't looked after the entire time it was HUO, same ball, same rubbers etc. PF has ball swirls and wear. If the mods don't fix the issue, I will follow your advice and also start looking at the connectors in between the drivers and the backbox. The ground wires from all 4 drivers come to 1 plug connector that goes to the ground bus, so there may be a problem there.

As far as to why the mod was done is a mystery but it does involve reversing the polarity of C1 so maybe the board design was wrong from the beginning.

I found the power distribution schematic online and printed it. I wanted to see what the 2 large caps in the cab do. I can only find C1 6800 MFD for the 12V circuit. The manual shows a 4800 MFD but I can't find it on this schematic.

Where did you get that schematic? The one I found is from the sys 80 service manual page 36. PDF file on Google. It only has a 24V circuit with a single rectifier and no C2. No 38V. I did change C2 from the begining with a 12000 mdf as per pinwiki. Is the 38V specific to HH and BH?

Thanks, I have the manual. I just overlooked that page.