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Thin End Of The Wedge...

Nedreud

Nedreud

Registered
Joined
Feb 12, 2013
Messages
3,092
Location
Aldershot, UK
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It's taken just over 4 years but I've finally got a pin IN THE HOUSE!

The missus got another rescue crow (she's a veterinary nurse) so half my pinshack got turned into an aviary. This meant I had nowhere to keep the bicycles so they were left out in the garden. I think she felt a bit bad so casually said maybe I could put a pin the house to make space for the bikes (else they'd have to go in the dining room). Of course, I jumped on the opportunity!

In typical pinball fashion though all the solenoids except the flippers have stopped working after the move so I can't actually play until it's fixed, but it does look pretty! Not an ideal location by south facing window but beggars can't be choosers.
 
Good result there Peter.

Mine has somehow ended up in the bedroom - yeah, go figure. Apparently she wanted it out of the spare room and would rather have it in our room than anywhere else. Maybe she'll change her mind once it's rebuilt and working. ;-)
 
kevlar said:
Well done Pete and nice to see you back, miss your super shiney threads :D.
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Thanks, @kevlar! Nice to be back. Just been so busy recently, but decided enough is enough and I want to get back to my pins! After lending VECTOR to @astyy to both clear space for me and provide him a working guide for his project rebuild, I was scuppered twice by refilling the space with another project pin, MR & MRS PAC-MAN, and an aviary for several rescued crows and magpies (which I love too - it's not just my wife!). But the crow flew off last night so I may even get the other half of the summerhouse back now. Regardless, it means that GOLD BALL can now be played anytime (my kids are pretty excited too) and I've got some space to get back to working on PARAGON! I'm very excited by the recent announcement that plans are under way to hold a pinball festival in Daventry in August 2018. If I can get all four of my games in working order I'll pack them in a transit and go!
 
Nedreud said:
In typical pinball fashion though all the solenoids except the flippers have stopped working after the move so I can't actually play until it's fixed, but it does look pretty
Click to expand...

The most likely cause of that on early solid-state Bally (and Stern) games is the fuse fitted under the playfield. It protects all non-flipper solenoids. Typically 1A slow-blow.
 
Jay Walker said:
The most likely cause of that on early solid-state Bally (and Stern) games is the fuse fitted under the playfield. It protects all non-flipper solenoids. Typically 1A slow-blow.
Click to expand...
That was my first thought too, and then some vague memory surfaced that I'd pulled the fuse to use of MR & MRS PAC-MAN whilst I was trying to fix the solenoid expander problems on that. Sure enough, I popped up the playfield and 1A SB holder was empty. But... after popping in a 3/4A SB (I don't have any spare 1A) the MPU controlled momentary coils still aren't firing (not many on GOLD BALL: 3 pops, 1 slingshot, 2 kickers and 1 knocker). The 3/4A fuse hasn't blown (unlikely with so few coils and as you know it's really there to prevent a stuck coil from overheating or kill a critical short circuit). At this stage I suspect a dodgy connection on the MPU or DRIVER board headers. They're IDC on GB. God, I hate IDC connectors. Replacing them with Molex KK crimps is on the to-do list!
 
:clap:YAY!!! :clap: SHE RIDES AGAIN!!! :clap:

Found and fixed the problem: solenoid drive transistor Q37 was closed circuit (dead) which was firing the left pop bumper continuously, which was blowing the under-playfield 1A Slow Blow fuse (I was using a 0.75A as I'm out of 1A) in about 1-2 seconds. Replaced Q37 with a brnad new TIP102 and replaced associated diode CR4 and the coil diode with new 1N4007s.

It's pinball time...
 
For future reference, I just remembered that occasionally the left pop bumper would buzz slightly and then fire in attract mode. I guess this was the warning sign that the TIP102 Q37 was beginning to fail before eventually going closed circuit. This is the second Q-transistor to fail on this unique solenoid/driver board. Think I'll replace the whole lot.

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Paul R Owen said:
What does that big square thing with numerous slats do??
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As @Wiredworm said, it's a heatsink to dissipate heat from the transistor (the silver thing in the middle). In this case it's an LM323 3 Amp 5 Volt Regulator which supplies the power for the MPU. By today's standards it's completely overkill and not that good. The 5V regulators are obsolete and quite hard to get hold of usually costing around £15-30 from suppliers of old components (which is why I bought 10 when I found them on eBay for a £1 each!). Someone has now designed a modern direct replacement using surface mount components:

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@myPinballs - have you seen these before? Only just come across them recently? http://news.ezsbc.com/lm323-replacement/ drop-in switch-mode apparently.
 
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