One thing that annoys me with all of them - they were all too cheap to install real test points. Just to save a few pennies! When I see this, all I can think is "where else did they cut corners"?

Out of those choices - the one at Marco looks best. The designer knew enough to put as many high current traces as possible on the *bottom* side of the board where the high current connectors are soldered onto the board. The Marco board appears to be the same as K'sArcade except the Marco board has heat sinks on the two bridges.

The original boards were easily repairable. Did you check the fuse and fuse clips associated with TP4?

Great Informative First Post!!
Welcome to Pinside!

Intermittent is often a connector issue. Most probably there is at least one plug in there that needs repinning.
For good info - see here:
https://www.pinwiki.com/wiki/index.php?title=Bally/Stern

barakandl has replacement rectifier boards at https://nvram.weebly.com/new-pcbs.html but I don’t see the 2518-54 listed. His quality is excellent, if he has one I’d consider buying his.

I have the Marco one in my flash Gordon and i also used on in a friends eight ball Deluxe that i fixed. Great boards.

I actually Just ordered the blank PCBs. Made the first prototype one a couple years ago and put it on the shelf for other things. Had some time lately so got this back out. Split the GI into two fuses. 43v bridge changed to 10a10 diodes. Feature lamp bridge will go on the bottom and mount against the large bracket like the original board did. Put the holes in so will be able to put the plastic shield over it. Traces are very wide and most are on the bottom. Any connectors with a top side trace connection has extra through holes to pass to the bottom side.

I have to buy different bridges though. Was not paying close enough attention but the Vishay brand GBPC35XXW bridges are only around 0.3" inches thick where the original (normal) are 0.45" thick so they will not mount right here.

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I would be all over this when you get it finished, like your DIY products. How are things looking for the reselling of the MPU boards?

MPU back in stock soon, probably before end of the week.

Bravo!
I just don't understand why others aren't using that big thermal mass of the base plate to help keep that bridge cool.

The KBPC35XXW are the thicker bridges.

Yeah, I am not sure either. Maybe to get the layout they wanted they could not place the bridge's center hole where it lines up with the bracket. Putting bridge on the top also likely blocks from using the drip shield if the bridges heat sinks are tall. The designs without any heat sink on this bridge are going to get smoking hot.

Thanks for that part number, I will have to look for it. I have always shopped in the GBPC350XW part number. Was buying Fairchild ones for a long time which are thicker type. They got more expensive when On Semi bought them out so I tried Vishay. Now I have a couple hundred of the thinner ones. They still have the 35a rating as the thicker Fairchild ones but have to figure the thicker ones have better thermal properties. I did upgrade the heat sink on the -16 rectifier to a 35x35x17mm heat sink designed for bridges. Seems to great for bridges so I can still use up those Vishay bridges there and some other places.
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For bridge rectifier thickness between GBPC versus KBPC -- it is the specific manufacturer that makes the difference.
For example -
Fairchild / ON-Semiconductor GBPC is 10.97 to 11.23mm thick.
Taiwan Semconductor - GBPC is 10.97 to 11.23mm thick.
MCC GBPC is 7.4 to 8.5mm thick.
Doitec Semiconductor KBPC is 7.2mm to 8mm thick.
EIC Semiconductor KBPC is 7.1 to 7.9mm thick.
Vishay GBPC is 7.4 to 7.9mm thick.

SIC (whoever they are) and Comchip seem to be the only ones that follows the KBPC being thicker than GBPC.
SIC GBPC is 7.5mm to 8.1mm thick.
SIC KBPC is 10.97 to 11.23mm thick.
Comchip GBPC is 7.5 to 8.5mm thick.
Comchip KBPC is 10.77 to 11.23mm thick.

All of the ON-Semi (formerly Fairchild) bridges that I have been getting have been the thicker style.
ON-Semi did what they do best - they hiked the prices for their bridges to the moon and won't budge on pricing. I don't care for Vishay - the leads turn black far too soon.

Just as bad - have seen what has happened to Aavid heat sinks? Bought out by Boyd and prices have quadrupled since January. Looking into getting heat sinks custom made to compete with the 6222BG heat sinks. The heat sinks shown in last photo - too bad they don't publicize the thermal resistance of these. Those work but are actually a hair too big for bridge rectifiers, would have been better at 29x29mm.

Besides those brand X ones I posted above for bridges have been buying CUI heat sinks lately. They seem like new brand and I found many similar to Aavid products that are a lot better priced.

CUI has been around for quite awhile - we use their wall warts quite often, they work well.
They're new to heat sinks but they won't make bridge rectifier heat sinks. I know - I asked.

On the -16 rectifier board, as you're now using discrete diodes for the 12V and 43V rectification, at some point you can probably also move that feature lamp bridge to the back side of the board lined up with the original screw hole since there's no other bridges to get in the way anymore.

Will you be supplying thermal transfer paste with your -54 rectifier board and if so, what thermal conductivity spec are you looking at?

Yes, I buy the little ketchup packets of heat sink compound for the kits which would go with the -54. I forget what spec they are, china grey grease, it is adequate here.

With the -16 rectifier I will investigate putting the bridge on the back. May have to include (different) new mounting hardware and I guess the slug thing attached the all three bridges would be not used. Free heat sink is attractive.

You might have to include a screw for the bridge in case the owner doesn't have them for what ever reason. I think they are 1" long, #8-32 thread?? can't remember - best to check.

I was thinking about the PCB stand off height versus bridge height on the back of PCB need to be near equally matched, but yeah screw length to be considered too.

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Are these for the -54 rectifier board? Does the screw for the optional standoff fit through the threaded hole in the large base plate?

Those stand offs above are for the -18 rectifier. I would like to find a source press in pcb stand offs bally used in the pennies each range. 20201103_184423 (resized).jpg

Prototype seems to be ok. I have a few things to tweak.

As far as the test posts vs pads. It is not the cost of the post but assembly. Any shortcuts in hand assembly are taken. I buy diode and resistor arrays at higher cost than discreet parts because assembly is easier. Seriously considering pick and place machine, reflow oven and solder stencils but a good setup is expensive. So far farming out assembly is not making $ sense. Nice little business hand assembly but at a limit of what can be done per time. Need more low hanging fruit like relay boards.
20201103_184041 (resized).jpg

barakandl

Any update on these new 2518-54 boards? You are my go-to when replacing Bally sound or rectifier boards.

Thanks,

WP

How are you making out with these? Im in need of some.

I would contact him directly. Not a great idea to try for a response on social media in most cases.