(Topic ID: 203770)

Gottlieb system 1 memory issue

By ChrisPINk25

6 years ago



Topic Stats

  • 8 posts
  • 4 Pinsiders participating
  • Latest reply 6 years ago by ForceFlow
  • Topic is favorited by 1 Pinsider

You

Linked Games

Topic Gallery

View topic image gallery

2017-11-29_07h48_20 (resized).jpg
C3B319B1-EC24-4351-BFF5-9B8731DFD909 (resized).jpeg
5B036C07-A669-43A3-A627-F632EFE324B5 (resized).jpeg
A0657FE6-4AA9-43D2-9A6B-B7C2F720513E (resized).jpeg
DF5F6CCD-638B-44F4-995A-FF6260DC49C9 (resized).jpeg
FB6950C4-0CDE-4B92-93EC-68926BC61310 (resized).jpeg
99360810-FE6B-46E1-9E9E-4BACA7C80F56 (resized).jpeg
AD6850CF-7FF2-4116-8577-1E6B68A6D800 (resized).jpeg
F1D89D99-A659-4078-AF8D-87BC5CE4F811 (resized).jpeg

You're currently viewing posts by Pinsider noflip95.
Click here to go back to viewing the entire thread.

#6 6 years ago
Quoted from ChrisPINk25:

... Here's the weird thing. The voltage at Pin 22 now reads 1.471v. What could cause that? I checked the battery pack multiple times and it was reading just below 4v.

Hi, looking at your battery pack, everything looks OK. The three cells delivers about 3 x 1.5 volts, so 4.5 volts. Then the protection diode (your pictures show it mounted in the right position) drop the voltage for about 0.6 volts, and you get at final a bit less than 4 volts. So, nothing wrong here.

On GTB SYSTEM 1, the memory power schematic is quite simple.
The diode CR26 prevents the current from going back in all the circuit. The R133 is use to charge the original NI-CAD battery.
VAB is the memory voltage, that power the 5101 RAM and the 4528 CMOS (Z2).
2017-11-29_07h48_20 (resized).jpg2017-11-29_07h48_20 (resized).jpg

There is no reason for the voltage to drop to 1.4 at pin 22 (VAB for 5101), unless:
- the diode CR26 is died, and don't stop the current
- you connect the battery pack at a wrong point

In both cases, the whole board is powered by battery, that is of course, insufficient. This can cause the voltage to dramatically drop.

Check the voltage on both pins of CR26 (this diode is located just above the NICAD battery): on cathode you should have about 4 volts, and nothing on the anode.

Promoted items from the Pinside Marketplace
From: $ 2.99
$ 7.50
Electronics
That Old Pinball
Electronics
From: $ 10.00
Playfield - Protection
UpKick Pinball
Protection
From: $ 5.95
Playfield - Protection
The Pinball Scientist
Protection
$ 89.00
Electronics
That Old Pinball
Electronics
$ 5.95
Playfield - Protection
The Pinball Scientist
Protection
Hey modders!
Your shop name here

You're currently viewing posts by Pinsider noflip95.
Click here to go back to viewing the entire thread.

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


This page was printed from https://pinside.com/pinball/forum/topic/gottlieb-system-1-memory-issue?tu=noflip95 and we tried optimising it for printing. Some page elements may have been deliberately hidden.

Scan the QR code on the left to jump to the URL this document was printed from.