(Topic ID: 288227)

Battery replacement on a 1st Gen Zaccaria pin

By Thistle

8 months ago



Topic Stats

  • 6 posts
  • 3 Pinsiders participating
  • Latest reply 8 months ago by luvthatapex2
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

View topic image gallery

IMG_2554 (resized).jpg
Zaccaria_MPU1_Battery.png

#1 8 months ago

Morning everyone,

First off... I'm brand new around here and would like to apologize in advance for any gaffs.

I've just blown the dust off of a '78 House Of Diamonds that was in my house growing up and been under a drop cloth for 30 years. I have a 13 year old son that's super keen to get it running and he and I are going to (attempt to) tackle whatever it needs on our own.

I don't know why I expected it to just start working when we plugged it in, but other than the odd playfield light coming on, it wouldn't accept coins so we quickly turned it off and started our research which of course pointed me almost immediately to the battery on the board as our first culprit.

The battery is still putting out a slight current but nothing near the 3V+ it's supposed to and there is definitely some corrosion in the immediate vicinity of the terminals, but fortunately nothing seems to have travelled far and the surrounding components seem unaffected.

I've desoldered the battery and cleaned the board up and I believe we're ready to install a replacement.

I've ordered a CR2032 holder and what I believe is the correct diode (1N4148) to prevent battery charging, but this is where my question comes in.

Nowhere online have I managed to find a definitive and clear explanation of how these two components need to be connected. It's worth mentioning at this point that I have only the most rudimentary knowledge of electronics and desperately want to avoid harming the machine, but both my son and I are eager to learn.

Clearly if I was installing a rechargeable battery, I'd just connect the positive and negative terminals from the replacement battery to the spots on the board where the original battery was and we'd be done with it, but it's the location and orientation of the diode that has me stumped.

It seems that battery replacement is a very common operation so I'm hoping that somebody on here has some experience and tips for a pair of newcomers.

Thanks in advance!

Jeff

#2 8 months ago

Here is an explanation on Daves zaccaria site (www.zaccaria-pinball.com) on battery replacement. I have used the backup capacitors on my zac games when I had them.

Batteries
The biggest worry with a Zaccaria CPU board is the NiCd battery pack used to maintain the CMOS memory when the game is powered off. This battery pack is mounted at the top of the circuit board, in the center. If it starts to leak, the battery fluid runs down the board and ruins every component in its path. If you have a non-working Zaccaria game, this is the first thing to look for. If yours is working and hasn't leaked, PLEASE get the battery off the board and either use a 1F memory backup capacitor, or mount a remote battery immediately. If the battery has leaked, Clay's web site has a good recovery procedure for dealing with the corrosion and damage. After cleaning up and neutralizing the leaked fluid, remove and replace all components that were touched by the battery fluid, and all sockets on the board. Inspect the connectors and ribbon cables for signs of corrosion and replace as necessary.

To replace the original battery, a 1F 5.5V computer memory backup capacitor like Jameco P/N 142957 or Mouser P/N 555-1.0Z5.5 can be mounted on the CPU board in place of the battery pack and short leads used to connect it to the battery (+) and (-) traces, or a fly lead can be connected where the battery used to be and used to reach a remote battery pack.

To mount a remote battery pack, cut two wires to about 16" long, and solder them to the battery (+) and (-) pads. The other end I solder to a .100" two-pin connector snipped from an old PC floppy drive controller. I add a drop of JB Weld two part epoxy, then heat-shrink the connector, forming a small plug that is just the right size to connect a Radio Shack rechargable portable phone battery (Part #23-197, 3.6V, 350mAh, NiCad). Mount the battery on the left wall of the backbox with a velcro strap stapled to the wood, and you should never have to worry about battery leakage again. Replace the battery every few years, just to be on the safe side.

Quoted from Thistle:

Morning everyone,
First off... I'm brand new around here and would like to apologize in advance for any gaffs.
I've just blown the dust off of a '78 House Of Diamonds that was in my house growing up and been under a drop cloth for 30 years. I have a 13 year old son that's super keen to get it running and he and I are going to (attempt to) tackle whatever it needs on our own.
I don't know why I expected it to just start working when we plugged it in, but other than the odd playfield light coming on, it wouldn't accept coins so we quickly turned it off and started our research which of course pointed me almost immediately to the battery on the board as our first culprit.
The battery is still putting out a slight current but nothing near the 3V+ it's supposed to and there is definitely some corrosion in the immediate vicinity of the terminals, but fortunately nothing seems to have travelled far and the surrounding components seem unaffected.
I've desoldered the battery and cleaned the board up and I believe we're ready to install a replacement.
I've ordered a CR2032 holder and what I believe is the correct diode (1N4148) to prevent battery charging, but this is where my question comes in.
Nowhere online have I managed to find a definitive and clear explanation of how these two components need to be connected. It's worth mentioning at this point that I have only the most rudimentary knowledge of electronics and desperately want to avoid harming the machine, but both my son and I are eager to learn.
Clearly if I was installing a rechargeable battery, I'd just connect the positive and negative terminals from the replacement battery to the spots on the board where the original battery was and we'd be done with it, but it's the location and orientation of the diode that has me stumped.
It seems that battery replacement is a very common operation so I'm hoping that somebody on here has some experience and tips for a pair of newcomers.
Thanks in advance!
Jeff

#3 8 months ago
Quoted from luvthatapex2:

Here is an explanation on Daves zaccaria site (www.zaccaria-pinball.com) on battery replacement. I have used the backup capacitors on my zac games when I had them.

Thanks for that. I suppose if I went the capacitor route it's an easier install as it's just a direct replacement. My next question I suppose would be regarding the rating of the cap... that article suggest a 5.5V capacitor, but the battery I've removed is 3.6V. I just want to make sure I don't cook anything

#4 8 months ago

Looking at the MPU board schematics, if you go with a CR2032 battery all you need to do is remove resistor R1 to the right of where the original battery was.

Resistor R1 is used to charge the NiCad battery from the games 5 volt power-supply. Without the R1 resistor, the battery will be disconnected from the charge circuit.
Diode D3 just above R1 on the MPU board is already in series with the battery as a blocking diode. You do not need to add any extra diode with the battery.
Personally I replace diode D3 with a 1N5817 which has a lower voltage drop than a 1N4148 but if you're uncomfortable doing this, then just leave D3 alone.

If you're going with a super capacitor, you want it to be 5.5V rated. The charge circuit will apply more than 3.6V to it.

Zaccaria_MPU1_Battery.png

#5 8 months ago

Thanks, Quench. This is super helpful and exactly what I was looking for. I've compared that schematic to my board and definitely see exactly what's going on now. If the D3 replacement is going to improve things, I'll definitely look into getting a replacement component and making that change. Like I said, this is a hobby that my son and I are looking forward to and anything that we can do to improve this cabinet we'll tackle.

IMG_2554 (resized).jpg
#6 8 months ago

Nope its what you need and if you go this route you never need batteries again.

Quoted from Thistle:

Thanks for that. I suppose if I went the capacitor route it's an easier install as it's just a direct replacement. My next question I suppose would be regarding the rating of the cap... that article suggest a 5.5V capacitor, but the battery I've removed is 3.6V. I just want to make sure I don't cook anything

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside