Hello fellow Pinside members,


I am having problems with my Centigrade 37. The lights do not alternate as they should. I have given all the info I thought could help as briefly as I can. I have also made a video showing the odd behavior and the relays mentioned below. Any help is much appreciated - and it’s o.k. to explain things to me like I’m a child. =) 

Here is a video showing the issues and relays mentioned below.
Thanks very much.



The Problem
* Centigrade 37 lights not alternating correctly
* Intermittent behavior
* Sometimes they work as expected
* Sometimes lights do not alternate at all
* Sometimes they will flicker - rapidly alternating back and forth several times when they should only alternate once. (See video)
* When in this “rapid flicker mode,” I’ve noticed the A-Relay under the playfield firing off and on (See video)
* Sometimes a gentle rap on the apron, side of the cabinet or engaging a flipper will produce the rapid alternating effect. (See Video)

Things I’ve Noticed
* Noticed that rapid flickering seems to be controlled/influenced by the A-Relay (See Video) 
* My “AS-Relay” is labeled “FS”
* The AS (FS?) Relay appeared to be in good shape (copper was clean and wiper moved freely) before cleaning it. 
* The contacts on the switch stack in the AS (FS?) Relay appear to show a build-up of matter - the contacts are not flat as I’d expect.
* The Match function works properly.

What I’ve Done About It
* Tried a variety of scenarios to reliable replicate the malfunction and cannot
* Read forums related to this issue
* Reached out privately to a very helpful Pinsider, MIKEO, who shared tips on refurbishing the AS-Relay (Thanks, @mikeo)
* Removed, disassembled, cleaned, reassembled, reinstalled the AS-Relay as indicated in Pinsider @ccotenj thorough guide found here: https://pinside.com/pinball/forum/topic/gtb-as-match-stepper-rebuild-step-by-step



Just Wondering…
* From what I’ve read, the AS-Relay seems responsible for the alternating lights, but the A-Relay under the playfield seems to have a role as well
* The innermost return lane on the left side doesn’t trigger most of the time - no scoring, chime, or activate the alternating lights. Under normal operating conditions, I’d expect this switch to alternate the lights when the ball rolls over it.
* Could the issue be related to this malfunctioning return lane? Perhaps a malfunction in the switch on the return lane is sending (or not sending) correct signals to trigger the A-Relay properly?



My Mechanical Background
* I can identify main parts of EM pinball machines.
* I can successfully make a halfway-decent solder connection.
* I can operate my toaster without burning my bread 98% of the time.
* I am willing and eager to learn.

This is my first time posting on a Forum. Please forgive me if I’ve not followed the correct protocol - I’m learning all kinds of new things! Thanks again.

Hey! Thanks very much for the information leckmeck and MarkG . I appreciate the quick, thoughtful responses and inclusion of schematics. I'll be honest, it'll take me a few careful reads to understand completely, but I get the general idea and feel like I know where to look.

I'm excited to dig in. Hopefully it'll be working fine this weekend!

Posting to document the process and running by those who know more than me before I go bending stuff.

I think I might have found something.

Picture 1) I took a look at the FS switch to verify the OR-GR and OR+GR wires were connected there.
1 FS OR-GR (resized).jpg

Picture 2) At the Drop Target closest to the flippers, I found the Drop Target SW OR-GR and OR+GR wires.
2_Drop_SW_OR-GR (resized).jpg

Picture 3) Drop Target Switch with drop target above playfield
A - The plastic piece on all other similar switches sits on the lowest blade - no gap.
B- Contacts don't appear to be having the best of connection possible
C - Top blade has previously been bent
3_Drop_SW_TU (resized).jpg

Picture 4) Drop Target Switch with drop target down. Other contacts touching.
4_Drop_SW_TD (resized).jpg

MarkG you mentioned adjusting the middle blade, but because of what appears to be a malformed top blade, I'm guessing I'd need to adjust the top blade to a position that would keep it relatively flat and close the gap between the plastic piece and the lowest blade. (photo 3 "A")

Thoughts?

I appreciate the clarification. I almost got in a philosophical debate with myself as to whether I was looking at Green with Orange or Orange with Green.

Apparently I not only missed the order of the "OR" and "GR", I also didn't notice the "+" and "-" indicators.

I'll correct the labeling to help prevent any future confusion.

Thanks for your help.

Happy to report that the problem is solved.

While straightening and adjusting the Drop Target Switch, I happened to notice a broken solder connection on the Bottom Target Switch.
Bottom Target Broken Solder (resized).jpg

When the bottom target is hit, the lights alternate. It appears the wires leading to the switch were making contact intermittently depending on vibrations made to the playfield. I'm guessing each time contact was made it was activating the alternating relay.

I've played about 20 games since soldering the wires back to the switch and all seems good.

Thank you all for your input and insights. I learned a bit about reading schematics, tracing wires through the machine, rebuilding a mini-stepper, adjusting switches, and careful observation.