New! Dark mode!

Browsing Pinside at night? Getting tired of all the white? Switch to dark mode using the button in the top right (or CTRL-B)!

(Topic ID: 192852)

Centigrade 37 capacitors and diodes


By Kramertheman

3 years ago



Topic Stats

  • 16 posts
  • 9 Pinsiders participating
  • Latest reply 3 months ago by KenLayton
  • Topic is favorited by 2 Pinsiders

You

Linked Games

Topic Gallery

There have been 4 images uploaded to this topic. (View topic image gallery).

c37 (resized).png
c37a (resized).jpg
c37 (resized).jpg
c37 (resized).jpg

#1 3 years ago

Can anyone explain what specific purpose do the capacitors and diodes serve in the EM game Centigrade 37? I can not get my Alternating relay to work and I have narrowed the problem down to these components. If I knew how these components related to gameplay it would probably help alot.

I am not a noob but far from an expert with schematics and pin repair. From what I can tell there is a capacitor and two diodes that relate to the alternating relay. The alternating relay is not an interlock relay. It looks like it always has power being applied when it is on. There is more than one switch in the path but basicaly it turns off and on with the match relay activity. If the game ends and the alternating relay is powered on, it stays powered on. It looks like the capacitor (and diodes) is there to drain the power to the Alternating relay and turn it off before it burns up. Am I right or am I totally off here?

There appears to be a capacitor in the circuit that awards a replay for a match and/or a score award replay. The PC boards on the decagon units related to these functions seem to get pitted and actually holes burned through the traces. Is the capacitor on these circuits an attempt to alleviate this issue? Is the fact that this capacitor is 40 years old (and likely failed) the reason these boards get pitted?

Any input is greatly appreciated.

Kramertheman

#2 3 years ago

A little circuit snip-it would help. A resistor/diode/capacitor circuit acts as a timed delay for activating a relay, aka flip a card/spin a card. I cant remember if the same is used on c37

#3 3 years ago

Hi Kramertheman
in here i made some theory: https://pinside.com/pinball/forum/topic/centigrade-37-alternating-relay#post-3704420 --- want to show the complete wiring (with the switch on the right) ? Greetings Rolf

#4 3 years ago

I borrowed this pic from a related pinside post. This is just the circuit relating to the alternating relay. There are two sepaate make/break switches to the right of the ?. One switch is on the fs match relay. There are two positions for this switch. There is also a switch on one of the drop targets . There are two positions for this switch. Positions for both of these switches have to line up for the circuit to complete.

The capacitor for the replay circuit is on a different part of the schematic.

I will get some snippets of my own of the schematic later today.

Kramertheman

c37 (resized).jpg

#5 3 years ago

Thank you Rolf, it was your post I borrowed the pic from. Your theory sounds like what I am thinking. To the right where your question mark is, there are two make/break switches. The alternating relay is not an interlock relay. There is one coil. The circuit is not a pulse. It is either off or on even when the game is over. Am I correct in thinking this circuit was to protect the alternating relay from burning out?
Wouldn't it have been easier to make it an interlock relay?

I'll get some pics a little later.

Kramertheman

c37 (resized).jpg

#6 3 years ago

OK, here are snippets of my schematic. Ultimately what I am trying to do is to get my alternating relay on my Centigrade game working.

The questions I pose to the group here is

What is the purpose of capacitors and diodes in these circuits and can I effectively get the alternating relay working by bypassing these components in the circuit on top?

I am keeping in mind that my problem may actually lay with the alternating relay coil itself. I still need to check the resistance of the coil.

Any ideas?

Kramertheman

c37a (resized).jpg

c37 (resized).png

#7 3 years ago

Looking at the schematic, it looks like it might be to supply rectified DC to the coil. The coil appears to have certain switch states where it could be on for quite awhile. DC current would allow for a smaller coil an keep the heat down.

Diodes can be checked and/or replaced for about 3 cents. Caps can dry out and can be replaced for a buck.

If it was my game, that wouldn't be where I look. I would check to see if you ever get voltage at the coil.

#8 3 years ago

I ordered a cap but I can't find an exact replacement for the diode. Referencing a different different thread I ordered a higher rated diode. At this point I am assuming the 40 year old cap is bad and using my multimeter and basic understanding of electronics at least one of the diodes is bad. The diode appears to be completely open. I am not sure how to check the actual coil to see if it is good or bad. I disconnected the wires going to the lugs on the alternating relay and applied the power (measured at 28 volts ) from the coin lockout coil and the relay tried to pull in but didn't seem to have enough strength to actually do it. I may have to order a replacement coil also.

Kramertheman

#9 3 years ago

I'd hold off on the coil.

I think a 1N4004 diode would work there.

I would put the diodes in, since you say they tested bad. I would put the cap in, since you already seem to have it.

Then, to test the coil, I would jumper a wire past all those switches. See if the coil pulls in.

#10 3 years ago

Success!! I replaced both diodes and the cap in the alternating relay circuit and now all seems to be working fine. When I was taking out the old 40 year old diodes they actually crumbled in my hand. It appears the DC current provided more power to pull in the relay. Thats why the AC 25 volts I was applying to the coil wasn't doing the trick.

On another note, Would a 22 microfarad capacitor work in the backbox to replace the 25 microfarad capactor that is called for? I cant see any ill effects but I would assume the original cap is bad and I can't find a 25 microfarad exact replacement. I'm not sure what the purpose of this capacitor is. Alternately if anyone knows where to find a 25 microfarad capacitor please let me know.

Kramertheman

#11 3 years ago
Quoted from Kramertheman:

Alternately if anyone knows where to find a 25 microfarad capacitor please let me know.

www.mouser.com

#12 3 years ago

Digikey.com recently added a cheap shipping option, $3.39 for up to 8 oz.

The most commonly sold electrolytic capacitors are give or take (+/-) 20% of the rated value.

#13 3 years ago

I love a story with a happy ending!

3 years later
#14 3 months ago

Just out of curiosity, and for further reference to others with a similar situation, what replacement diodes did you use?

#15 3 months ago
Quoted from Kramertheman:

On another note, Would a 22 microfarad capacitor work in the backbox to replace the 25 microfarad capactor that is called for? I cant see any ill effects but I would assume the original cap is bad and I can't find a 25 microfarad exact replacement.
Kramertheman

Normal replacement procedures as relating to electrolytic capacitors is to step up to the next highest standard value if you can't find the original value.

Since the original is 25 uf, the next step up logically is 33 uf. However, an EM pinball is not rocket science and tolerances on components can vary. You should still be ok using a 22 uf one.

#16 3 months ago
Quoted from PinWiz1969:

Just out of curiosity, and for further reference to others with a similar situation, what replacement diodes did you use?

In my opinion, a 1N4004 would be perfectly fine to replace the original diode.

Promoted items from the Pinside Marketplace
From: $ 18.00
Apparel - Men
Pinside Shop
From: $ 0.80
Playfield - Other
Rocket City Pinball
$ 55.00
Various Novelties
Pinball Photos
$ 7.95
Apparel - Unisex
Pinball Wheezer
$ 209.99
From: $ 22.95
Playfield - Protection
ULEKstore
$ 26.50
Playfield - Toys/Add-ons
The MOD Couple
$ 55.95
Boards
Allteksystems
$ 4.49
Electronics
Yorktown Arcade Supply
$ 5,999.00
Pinball Machine
Nitro Pinball Shop
$ 20.00
Playfield - Toys/Add-ons
To-Go Cup - LED Out of stock
UpKick Pinball
$ 28.50
Playfield - Toys/Add-ons
ULEKstore
$ 22.00
Cabinet - Sound/Speakers
ModFather Pinball Mods
From: $ 18.00
Playfield - Plastics
Ramp-O-Matic
$ 51.45
Playfield - Toys/Add-ons
Lermods
$ 79.99
Cabinet - Armor And Blades
PinGraffix Pinside Shop
$ 10.00
Cabinet - Decals
Pinball Haus
$ 5.00
Cabinet - Other
Pin Monk
$ 5,899.00
Pinball Machine
Great American Pinball
$ 24.00
Playfield - Other
Pin Monk
€ 8.10
Flipper Parts
Buthamburg
$ 44.00
Playfield - Toys/Add-ons
Lermods
$ 84.95
Cabinet - Shooter Rods
Super Skill Shot Shop
$ 27.00
Electronics
Yorktown Arcade Supply
From: $ 175.00
Playfield - Toys/Add-ons
Williamson Pinball Mods
$ 254.99
$ 4.49
Electronics
Yorktown Arcade Supply
$ 25.00
Playfield - Toys/Add-ons
3D Tech. Pinball Parts

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