Simplex module 556-915a search question

Hello all,

I have a customer that with a older Simplex Fire Panel. I have narrowed the problem down to a particular board or module.
The board is part number 556-915A and is a single zone card.

My first question is, does anyone know of a source for a replacement board??

My second question is can anyone tell me if a 556-915C board be a alternate replacement if the “A” version is unattainable??
Or what is the difference between the two boards??

I know I am asking about equipment that is older than dirt but it would be great if someone has a some knowledge they can share.

Appreicate any help.

Thanks,

Les

Is that 556-915 number on the component side of the board or on the non component side of the board? Is it ink stamped or part of the foil etch? I ask these questions because an old parts list I have does not show a 556-915 but does show a 556-916 (N/O Zone). Many times these older boards have the bare board number at 1 digit less than the finished assembly number. The bare board number is usually part of the etch pattern while the finished assembly number is the ink stamp number on the component side.

The revision letter usually does not matter on replacing boards 99.9% of the time. The rev letter is incremented when there is a change made to the board for a technical improvement, component substitution, or other reason. The information about the differences in rev letter would be in change orders that were never seen the outside of the factory.

Best of luck finding one.

Thanks for the quick reply.

The number 556-915A is on the non-component side of the board at the end near the face plate.
The numbers are etched in or as part of a solder wave. Is this the part number or is it somewhere else??

The same applies to the other board 556-915C
On this board it has a different switch with a center (disc) label.

From what you are saying then that would be the upgrade or better version of sorts, correct??

Thanks for the assist.

Les

The number on the non component side in the copper etch is the number of the bare circuit board with no components installed. What you have are two different finished assembly boards each built on the same bare (no components) circuit boards. They do the same job but one has the test/disconnect switch and the other doesn’t.

The one without the switch most likely is a model number 2001-1018, service part number 556-916. The one with the switch probably is a model 2001-1020, service part number 556-540, although both could be a different finished assembly boards. It is entirely possible that the same bare board was used for finished assembly boards other than the two mentioned. The part numbers should be ink stamped on the component side of the boards usually along the edge somewhere in very small lettering.

STR-SG Excellent!!!

That is very helpful. Now I know what I need to look for.
Will do more investigation tomorrow.

Thank you very much!!

Les

Here is a link to a 556-916 being sold on Ebay. One of the pictures shows the ink stamp part number.
http://www.ebay.com/itm/SIMPLEX-556-916-Zone-Module-Certified-Good-by-Simplex-USED-/131728062744

Good Morning STR-SG,

I now have more detail in my quest. I may have misled you a bit previously. I did not have the bad board 556-915A in front of me at the time and thought that the switch was just a two position with a (Norm) and (Alarm Test) functions. The one that I was looking at as a replacement was posted as a 556-915C which has a (DISC) position between the other two. In other words a 3 position switch. My thinking at the time was that was the difference.

Now that I have the bad board with me they actually have the same configuration. The only difference that I can see other than color of the capacitor and some other components is the stamped or printed number on the component side of the board.
The bad board has stamped 556-540G and the other has a handwritten 556-540J.

Based upon the input you have provided the J board would be a newer generation of the same board.
Otherwise they are the same board and can be swapped accordingly. Is that correct??

Thanks again for any assist. All very helpful.

Les

You are correct, the 556-540G and the 556-540J are interchangeable with the J version being a newer revision board.

Great!! Give yourself at least 10 bonus points!!

Thank you very much!!

Les

STR-SG,

A couple of other questions that came up.

This is a link to a couple of pictures of the component side of the board.
https://www.dropbox.com/sh/2erjiog3svv8ew1/AAAPLArDw2rlmVc6SkNbdFwCa?dl=0

In the one picture I have placed a couple of arrows. The one points to the back of the board were the diodes are located.
The one at D26 has been cut. I assume that is for some feature that was needed or not needed for the application.
I have see this before on other simplex boards. Any concerns there or should I duplicate on the replacement board??

At the second arrow in the oval. It is showing a trace that was cut by a tool. You can see the scratches in the board.
Can you think of any (good) reason that would be done??

Again thanks for the input.

Les