Author Topic: PHYSICAL DIFFERENES BEWTEEN 502 VS 504 Boards (Read 3102 times)

brettsrt · « **on:** September 17, 2020, 04:48:12 PM »

What are the physical differences between the 502 and 504 boards? can a 502 board be converted to a 504 board? The look very similar...

qbert · « **Reply #1 on:** September 17, 2020, 04:52:45 PM »

The short answer is no.
IGT relocated the traces on the board to eliminate the hum issue. They are different.

brettsrt · « **Reply #2 on:** September 17, 2020, 04:53:18 PM »

So the PCB is different basically

Quote from: qbert on September 17, 2020, 04:52:45 PM

The short answer is no.
IGT relocated the traces on the board to eliminate the hum issue. They are different.

qbert · « **Reply #3 on:** September 17, 2020, 07:55:02 PM »

Correct

Retro tech repair · « **Reply #4 on:** September 20, 2020, 09:32:19 AM »

The early 50x boards had poor grounding for the audio section of the board. The 504b has a ground plain that actually ties into the board tray to fix the hum. I have seen 504a boards that have had the geounds reworked using wires under the board they don't name the hum perfect but they do help a lot. I have lost all pictures of how to do this modification tho i may have posted them on the old site but im not sure.

shortrackskater · « **Reply #5 on:** September 20, 2020, 09:41:42 AM »

Quote from: Retro tech repair on September 20, 2020, 09:32:19 AM

I have lost all pictures of how to do this modification tho i may have posted them on the old site but im not sure.

What was your user name on the old site? I might be able to find them.

I found it "vtyler" correct?

Retro tech repair · « **Reply #6 on:** September 20, 2020, 09:48:07 AM »

Quote from: shortrackskater on September 20, 2020, 09:41:42 AM

Quote from: Retro tech repair on September 20, 2020, 09:32:19 AM
I have lost all pictures of how to do this modification tho i may have posted them on the old site but im not sure.

What was your user name on the old site? I might be able to find them.

I found it "vtyler" correct?

Yes im looking through one of my old backup drives also. I will also check my boards tomorrow when im back at my shop.

shortrackskater · « **Reply #7 on:** September 20, 2020, 09:59:52 AM »

I just combed through the archive site and couldn't find anything. There is a LOT on the two boards though on both the current site and the archive site.
Hope you can find them.

Retro tech repair · « **Reply #8 on:** September 20, 2020, 11:05:05 AM »

i found it but the file is too bit to upload here i will try cropping it and see if i can get the size down.

edit:ok i cropped the image down and i added color over the wires that intersect to better show wire paths.i have done the same mode to a few boards and it makes the hum a lot better. i have not looked into what exactly its doing.

edit2: looking at the schematic it looks like they are just reinforcing the power and ground connections. i wonder if we linked the gnd into the chassis like the 504b boards do if it would make it even better. i have some boards i need to repair maybe i will do this mode to one of them and try both.

Retro tech repair · « **Reply #9 on:** December 05, 2020, 11:37:48 AM »

Just pulled this out if a machine i have had in storage for a wile. I got the machine directly from the casino so i know the mod has to be atleast from a casino level now. I have done this mod to a number of boards after discovering it and it does help a good bit, but I would not consider it true 504 quality.

Stayouttadabunker · « **Reply #10 on:** December 05, 2020, 11:49:32 AM »

I've seen that mod

with one of my 502's of the last bottom photo you posted.

Always wondered why it was there.

I will see if I can find that MPU, and do some sound comparison tests against another UN-modded 502 and against a 504.

Retro tech repair · « **Reply #11 on:** December 05, 2020, 12:00:21 PM »

Quote from: Stayouttadabunker on December 05, 2020, 11:49:32 AM

I've seen that mod with one of my 502's of the last bottom photo you posted.

Always wondered why it was there.

I will see if I can find that MPU, and do some sound comparison tests against another UN-modded 502 and against a 504.

I actually think i have an un modded 502 a modded 502 and a legit 504 b now that I found this board.

DB26 · « **Reply #12 on:** December 05, 2020, 12:33:42 PM »

Cool mod. Would this be a better choice than adding the resistors in line with the speakers?

Retro tech repair · « **Reply #13 on:** December 05, 2020, 12:45:15 PM »

Quote from: DB26 on December 05, 2020, 12:33:42 PM

Cool mod. Would this be a better choice than adding the resistors in line with the speakers?

Im personally not a fan of putting resistors on the speakers. I donâ€™t actually see a big difference in the machines that have been brought in with them.

DB26 · « **Reply #14 on:** December 05, 2020, 01:42:02 PM »

I think I might do this mod to my 504A board. Looks easy to do.

Ken · « **Reply #15 on:** December 05, 2020, 01:58:16 PM »

Going through a box of boards and I have one with the paper sticker on it too. Serial number starts with a D which is commonly found on 502 boards and 504s started with E.

Retro tech repair · « **Reply #16 on:** December 05, 2020, 02:04:07 PM »

Quote from: Ken on December 05, 2020, 01:58:16 PM

Going through a box of boards and I have one with the paper sticker on it too. Serial number starts with a D which is commonly found on 502 boards and 504s started with E.

Actual 504b boards that have not been modified have a grounding pad around some of the mounting screws.

Ken · « **Reply #17 on:** December 05, 2020, 02:23:44 PM »

Here's a picture of a 504-B. Doesn't appear to be any mods.

lookes · « **Reply #18 on:** December 05, 2020, 02:35:03 PM »

Any idea on this one? It has white simm sockets that are often 502A boards.

Stayouttadabunker · « **Reply #19 on:** December 05, 2020, 02:39:23 PM »

Quote from: Ken on December 05, 2020, 02:23:44 PM

Here's a picture of a 504-B. Doesn't appear to be any mods.

Did you look underneath Ken?

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Author Topic: PHYSICAL DIFFERENES BEWTEEN 502 VS 504 Boards (Read 3102 times)