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Hi, I have a Barcrest King of Roulette (MPU4) that sat unused for about 13 years. It first showed a battery error, so I replaced the battery. Now it boots, but when I insert coins (or even add credit with the key) after 2–3 seconds it shows “BLACK BOX”. What usually causes this on MPU4 and what should I check first to fix it? Thanks!

Hi, I have a Barcrest King of Roulette (MPU4) that sat unused for about 13 years. It first showed a battery error, so I replaced the battery. Now it boots, but when I insert coins (or even add credit with the key) after 2–3 seconds it shows “BLACK BOX”. What usually causes this on MPU4 and what should I check first to fix it? Thanks!

Hi, I have a Barcrest King of Roulette (MPU4) that sat unused for about 13 years. It first showed a battery error, so I replaced the battery. Now it boots, but when I insert coins (or even add credit with the key) after 2–3 seconds it shows “BLACK BOX”. What usually causes this on MPU4 and what should I check first to fix it? Thanks!

Hi, I have a Barcrest King of Roulette (MPU4) that sat unused for about 13 years. It first showed a battery error, so I replaced the battery. Now it boots, but when I insert coins (or even add credit with the key) after 2–3 seconds it shows “BLACK BOX”. What usually causes this on MPU4 and what should I check first to fix it? Thanks!

Hi everyone,I’m hoping for some advice with my Barcrest King of Roulette (MPU4). The machine has been in storage for about 13 years. When I powered it up it originally showed a battery error, so I replaced the battery. After that the machine boots and plays the intro/attract, but when I insert coins it will accept them briefly and then after about 2–3 seconds it shows “BLACK BOX” on the display. It also happens if I add credit using the key/service method (so not only with coin insertion) — after a couple seconds it still ends up with BLACK BOX. Does this point to a coin mech/validator issue, an I/O fault, or possibly RAM/NVRAM corruption from sitting for so long? What are the best first checks to diagnose this (connectors, DIP settings, clear/ram reset procedure, etc.)? How can I fix it and get the machine working again (even in free play just for testing)? Thanks in advance for any help!

Hi everyone,I’m hoping for some advice with my Barcrest King of Roulette (MPU4). The machine has been in storage for about 13 years. When I powered it up it originally showed a battery error, so I replaced the battery. After that the machine boots and plays the intro/attract, but when I insert coins it will accept them briefly and then after about 2–3 seconds it shows “BLACK BOX” on the display. It also happens if I add credit using the key/service method (so not only with coin insertion) — after a couple seconds it still ends up with BLACK BOX. Does this point to a coin mech/validator issue, an I/O fault, or possibly RAM/NVRAM corruption from sitting for so long? What are the best first checks to diagnose this (connectors, DIP settings, clear/ram reset procedure, etc.)? How can I fix it and get the machine working again (even in free play just for testing)? Thanks in advance for any help!

Hi everyone, I’m hoping for some advice with my Barcrest King of Roulette (MPU4). The machine has been in storage for about 13 years. When I powered it up it originally showed a battery error, so I replaced the battery. After that the machine boots and plays the intro/attract, but when I insert coins it will accept them briefly and then after about 2–3 seconds it shows “BLACK BOX” on the display. It also happens if I add credit using the key/service method (so not only with coin insertion) — after a couple seconds it still ends up with BLACK BOX. Does this point to a coin mech/validator issue, an I/O fault, or possibly RAM/NVRAM corruption from sitting for so long? What are the best first checks to diagnose this (connectors, DIP settings, clear/ram reset procedure, etc.)? How can I fix it and get the machine working again (even in free play just for testing)? Thanks in advance for any help!

Hi everyone, I’m hoping for some advice with my Barcrest King of Roulette (MPU4). The machine has been in storage for about 13 years. When I powered it up it originally showed a battery error, so I replaced the battery. After that the machine boots and plays the intro/attract, but when I insert coins it will accept them briefly and then after about 2–3 seconds it shows “BLACK BOX” on the display. It also happens if I add credit using the key/service method (so not only with coin insertion) — after a couple seconds it still ends up with BLACK BOX. Does this point to a coin mech/validator issue, an I/O fault, or possibly RAM/NVRAM corruption from sitting for so long? What are the best first checks to diagnose this (connectors, DIP settings, clear/ram reset procedure, etc.)? How can I fix it and get the machine working again (even in free play just for testing)? Thanks in advance for any help!

Good evening, everyone. Thank you for taking an interest in my problem. So, T56 = BC172 (new) As are T57, T58, T59, and T60 (BC172) (new) T61 = ZTX510 (new) I'm going to do some checks, track checks and others. Thanks; have a good evening.

That's wrong, it should go high after about 1 second. This means there's something wrong in the RESET circuit. What did you replace as T56?

Hello, thank you for your guidance. So, on R and on Pin 34 of the PIA 6821, I'm finding a low level. Thank you.

Hi guys just a quick enquiry on the mpu4 clubber stake up emulation .can anyone tell me if there is a back door open mode on this as ive got a mate who cant seem to find it .it plays fine but wondered if its even possible ?? Obviously in door open mode and game play the reels can be moved to show wins on the win lines using the nudge buttons and I think the cancel button . Any pointers would be appreciated.

Good Morning, Reset line is on pin 34 of all the 6821`s and a few other places, also easier is the test pin above the power socket, see pic. Connect your logic probe, turn it on and report back what happens. 👍

Greeting from a long fruit machine playing old git in the UK

Good evening. Okay. How do I check and unlock it for this reset? Thank you.

Sorry not pin 11 going LOW to HIGH, the RESET line. If the board is stuck in RESET it won't do anything.

Hello. Yes, I confirm for MOD2. (14600/2) On pin 11 of IC24 , it's not working. I get a high level immediately upon power-up; no low level. I confirm; the RAM is indeed HM1-6561. Thank you for your help.

OK, the first thing is this is probably a MOD 2 board being as it has a 74LS03 as IC24. The output is now on pin 11. Does it come out of RESET? On switch on it should stay LOW for about 1 second then go HIGH. Do you have the correct RAM fitted, it takes the smaller RAM (in Bytes) 256x4. HM6561 or equivalent. Because of this it won't run later games. T62 doesn't appear in this revision of the board as it has a thyristor (T56) in the RESET circuit.

Hello everyone. I'm back for a short month. Maybe enough time to repair my second MPU3, if anyone would be willing to help. It won't start. I've replaced the capacitors around the regulator. The 104 capacitors on the MPU, the RAM (NOS), and the transistors in the reset area. (By the way, I don't know where T62 is on the schematic.) So, here are my readings based on what I've read about the MPU3 and my recent experience getting help from Midibob. IC24 74LS03, yes, new. IC10 Pin 3 - 561 Hz square wave. IC18 Pin 12 - 100 Hz R83-84-85-D43-C39 100 Hz R68 and R69 OK C32 and C34 OK IC24 Pin 8: I can't find 2 Hz; nothing. IC9 Pins 10 to 15: only high levels (logic probe). All components in this area have been tested or replaced if suspected. D44 and D45 are also new. No corrosion on the RAM sockets or underneath. Cartridge port is also free. Ah yes, the 5V is at 5.2V. The circled area contains all components that have been tested or are new. So, if you have any ideas where to look, I'm all ears. And whatever happens, we won't throw ourselves into the Thames. :)) Thanks in advance.

Yes mate, be good to see you. It's been years!

No worries and like you ive played quite a few clubbers and still do and much prefer them to awps . Im pleased there are still one or two still about .

Many thanks Sulzerned, much appreciated. Some very interesting points, too. 👏 Yes, I'd completely forgotten to mention that crazy "scavenger tech" whereby the machine would suck the last few bits of shrapnel in the player's pocket in 1ps, 2ps and 5ps for credits. I remember it now (and, yes, used it too), the alpha would display fractions of a credit, if distant memory serves. I'm biased of course, but I'd firmly agree with you: NbN isn't a patch on Razzle (but then, very few machines are IMO). So much more going on, more player options, more interactivity and hence more playability. Razzle was a much harder profile, too (especially for an MPU3); it could take a tenner in cash with very little happening, but on the other hand it could go token-crazy (multiple £3JPs in short succession, either off the 555+holds and/or multiple nudge JPs etc.) or put out a bonkers Danger Series (which, at least on the physical, well-played machines in the wild, sometimes did go for high credit-repeating amounts with multiple £1 wins etc). As an avid player of club machines back in the day, the stingy Super Series amounts off Barcrests - whether MPU3s like Sweepstake or Royal Exchange, or later MPU4 machines like Crackpot's Zipper feature etc. - were a constant source of disappointment, for sure. Old BFM System 83 clubbers (whose names I have long since forgotten) tended to be more generous, and some had a "Choose a win from 8" feature which would occasionally roll in the 4 melons for £25 (on 10p play). Fascinating to hear you once owned this machine!

"A M12 washers in the EM5 for pounds and the summer of 85 onwards they got absolutely blitzkrieged by them….so they say😆" 😁 Well, needless to say I didn't know about that one lol. Ironic, considering I was working in a sheet metal shop at the time & could've ready got my hands on a bag of M12 washers 🤦‍♂️ I could've well done with the cash at the time!

Very new newbie here. Amateur level electronics and curious about Fruit Machines in general.

Welcome back and great to read up on another machine post (youve done one or two 😉)yes sadly the mecca isn't as busy as it once was but is still a good place .sadly or happily there are many new forums on fb which have poached members which was always going to happen . Mmm yeah id agree with you on almost most points regarding nbn . It really wasn't a great game and desperately needed new features injected into an oldish idea . You could almost say it was made for the bingo hall environment and perhaps it was but I dont remember playing any in seaside arcades but oddly im sure I remember seeing at least one .I use to own one ,having purchased it from the late Mike stead (mds) and didn't gel to it .I was never a fan of the double/ nothing gambles these later mpu3 gave and much prefered the roulette wheel or straight ladder climb/reel spin type gamble of earlier machines . Each to their own pete but razzle was a far better machine in my opinion and possibly fortune numbers too even without an exchange when compared to nbn . I think it was an ongoing thing with barcrest and its special/super series win spins that they were from the outset very mean and we never got what we expected even with the club machines. Oddly the club machine s even stated a maximum of £100 could be won off special series but it never happened of coarse . I think the writing was on the wall once the tall cab came out with the likes of strike a light and odds on as nothing new was really injected into the mpu3 game play with odd exceptions like razzle and autoroute .it was only at the end of the mpu3 reign that big shot showed promise . I'd give naughty but nice a 5/10 too as I do like the sounds and artwork very much . Oh and just one thing you didn't mention was the intended inclusion of a scavenger type mech to accept 1p/2p&5p coins for credits. The only other to include this was autoroute both using em5 mechs which were very unreliable .what was going through the minds at barcrest was anyone's guess but probably a arcade owners worst nightmare sifting through 100s of 1p and 2p coins ! Imagine putting in 10x1p coins just for one credit 🤷🤦. Anyway great write up and most enjoyable and hope you can do a few more .👍