Gottlieb System 3 vertical lines on display

(Topic ID: 211624)

Gottlieb System 3 vertical lines on display


By arolden

8 months ago



Topic Stats

  • 14 posts
  • 3 Pinsiders participating
  • Latest reply 6 months ago by arolden
  • Topic is favorited by 1 Pinsider

You

Linked Games

Topic Gallery

There have been 7 images uploaded to this topic. (View topic image gallery).

2018-04-26_12h08_29 (resized).png
IMG_4972 (resized).JPG
IMG_4969 (resized).JPG
IMG_4970 (resized).JPG
IMG_4971 (resized).JPG
IMG_4968 (resized).JPG
IMG_4894 (resized).JPG

#1 8 months ago

Hi everyone.

Hoping someone can give me some guidance on this. I am helping a friend diagnose some issues on an SF2. The display has started to show vertical lines, evenly spaced across the display. They look very similar to the 2 lines in this image (http://www.pinwiki.com/wiki/images/thumb/5/5c/BadRAM-2.jpg/799px-BadRAM-2.jpg), but all the way across the display.

Now, the game and the display boot up fine so I do not think it is the U8G chip. The display works perfectly when a known-working display driver board is put in the game. So the issue is definitely on the board. However I am not sure which component to look at now. I am assuming one of the other ICs is bad, but which one? I'd say U1-U4 as a guess but I'm really not sure.

I also noticed that U3 is not listed in the manual - if anyone can advise what part number this is that would be helpful.

Any guidance is appreciated.

#2 8 months ago

Hi,

U3 is the DSPROM, it's a 512 KB - 27C020.
As the board boot, you can be sure that the GAL U8 is OK (as it decode the address map for RAM/ROM/VIDEO, if it's burned, nothing work ! but it's not the case).
The RAM (U4 - 6264 - 8KB), is shared between the video chip (U2 - 68B45) and the cpu (U1 - 65C02). It serve as general purpose memory, and video memory.
To access the RAM, an "address switch" is done by U9/U10/U1 (74LS157).

When there is row or column missing, most of the time the culprit is the RAM (U4).
The video chip, 68B45 can also be involved (default in addressing the RAM) or the switches (U9/U10/U1). But this is quite rare, check before for the RAM, it's easy to replace by a new one. Unfortunately, it's not mounted on socket.

#3 8 months ago
Quoted from noflip95:

Hi,
U3 is the DSPROM, it's a 512 KB - 27C020.
As the board boot, you can be sure that the GAL U8 is OK (as it decode the address map for RAM/ROM/VIDEO, if it's burned, nothing work ! but it's not the case).
The RAM (U4 - 6264 - 8KB), is shared between the video chip (U2 - 68B45) and the cpu (U1 - 65C02). It serve as general purpose memory, and video memory.
To access the RAM, an "address switch" is done by U9/U10/U1 (74LS157).
When there is row or column missing, most of the time the culprit is the RAM (U4).
The video chip, 68B45 can also be involved (default in addressing the RAM) or the switches (U9/U10/U1). But this is quite rare, check before for the RAM, it's easy to replace by a new one. Unfortunately, it's not mounted on socket.

Excellent; thanks for the information. I will replace U4 and see what happens. Luckily it is the same 6264 used by Williams and Stern so I have spares.

#4 8 months ago

I had a look at my Tee'd Off and Stargate to compare. Stargate uses a LH5168-10L chip and the Tee'd Off uses a 8464A-10L.

Any idea why they are different and why they are not 6264s?

#5 8 months ago
Quoted from arolden:

Any idea why they are different and why they are not 6264s?

It's simple, it's just a matter of procurement by the suppliers.
The manufacturer of the board will put the components he has on hand, according to his stocks. The origin and the brand may vary according to the wholesale prices, and also according to the availability on the market.

Reference 6264 is a generic to denote a CMOS static memory of 64 Kbits (8 KB).
Each suppliers uses his own reference. There may be differences, but they are always minor and mainly concern the power consumption.

Access time does not matter. -10 means 100 ns, -15 means 150 ns, and -80 mean 80 ns.
As, on the video board, the 65C02 and 68B45 are clocked at 3.579 / 2 = 1.8 Mhz, even a "slow" memory at 150 ns will fit nice.

Most of the time, they use reference 6264: HM6264 from Hitachi, CY6264 from Cypress, MK6264 from ST, HY6264 from Hyundai, U6264 from ZMD. But some are well known for using slightly more exotic references : MB8464 from Fujitsu, TC5564 from Toshiba. And sometimes, they are very far from this reference : LH5168 from Sharp, GM76C88 from Goldstar
But all are compatible and can be interchanged.

#6 8 months ago
Quoted from noflip95:

It's simple, it's just a matter of procurement by the suppliers.
The manufacturer of the board will put the components he has on hand, according to his stocks. The origin and the brand may vary according to the wholesale prices, and also according to the availability on the market.
Reference 6264 is a generic to denote a CMOS static memory of 64 Kbits (8 KB).
Each suppliers uses his own reference. There may be differences, but they are always minor and mainly concern the power consumption.
Access time does not matter. -10 means 100 ns, -15 means 150 ns, and -80 mean 80 ns.
As, on the video board, the 65C02 and 68B45 are clocked at 3.579 / 2 = 1.8 Mhz, even a "slow" memory at 150 ns will fit nice.
Most of the time, they use reference 6264: HM6264 from Hitachi, CY6264 from Cypress, MK6264 from ST, HY6264 from Hyundai, U6264 from ZMD. But some are well known for using slightly more exotic references : MB8464 from Fujitsu, TC5564 from Toshiba. And sometimes, they are very far from this reference : LH5168 from Sharp, GM76C88 from Goldstar
But all are compatible and can be interchanged.

Understood. Thanks for explaining that. The spare chips I have are Hyundai HY6264s.

I replaced U4 and installed a socket but unfortunately it made no difference. So that leaves U9, U10, U11 and U1.

U9, U10 and U11 all seem OK when probing with my DMM. All return the same values on all legs. However, I am not sure how to test U1.

#7 8 months ago

Bump! I'd appreciate more input on this. It's looking like I'll have to replace U9, U10, U11, U1 and U2 one after another until I find which chip was faulty. Does anyone have any advice as to which ones are more likely to fail, or which ones I should target first?

1 month later
#8 6 months ago

Another bump. I've just bought a logic probe so I can test these chips before shotgunning them all. However, I am having issues testing them. I have the probe connected to 5v and ground, and set to PULSE and TTL modes for testing the 72LS157 chips (U9-11). However when I put the probe on the legs of the IC, all of the lights are lit. No pulsing. I must be probing the wrong area. Can anyone tell me if those probe settings are correct and which pins I should be probing? I have read Terry's guide on logic probe use however it focuses on WPC so not quite the same.

Also, here's a picture of the actual problem.

IMG_4894 (resized).JPG

#9 6 months ago

Another update. I have replaced U9, U10, U11 and U2. No improvement.

I am still waiting on the U1 replacement to arrive so hopefully that will be it.

I've uploaded some photos of the board in case someone is able to spot an issue that I can't see.

Thanks for any help.

IMG_4968 (resized).JPG

IMG_4971 (resized).JPG

IMG_4970 (resized).JPG

IMG_4969 (resized).JPG

IMG_4972 (resized).JPG

#10 6 months ago

OK, looking at your pictures and as you replace the U4 RAM (considered as safe), the issue should be in the U13 area.

On the pictures, you can notice that 1 pixel on 8 in permanently lighted.
The first 7 pixels are ok, and the last 8th is always lighted.

On the video board, the datas are addressed by the 6845 CRTC from the memory (this chip don't care about the data itself, and is used only for addressing the video RAM). Basically, the datas are serialized/clocked and sent to the display using the RDATA/RCLK signals. The data to be transmitted to the display are selected by U13. This chip is a "data multiplexer" and select one bit among eight bits. The address is given by MA0..MA2 and the source is D0..D7 from the memory:
2018-04-26_12h08_29 (resized).png
The "Y" output reflect one of the eight entries (D0..D7) selected by the 3 bits selectors (S0..S2, aka MA0..MA2). Note also that, there is a pullup resistor (R7), so if an input is not wired, the default value at Y is "1"... so a lighted pixel. But on your board, R7 is not mounted (this resistor is not mandatory).

As there is one pixel permanently lighted, the issue is that at a time, the "data bit" is not transmitted but set to "1". As the first 7 bits are OK, and the last 8th is always 1, the culprit line should be D7 (or D0 - I'm not sure of the direction !). This may come from:
- a deffective RAM, but as you change U4, this option should be rejected
- a deffective U13, with a burned entry (D0 or D7
- a broken line at U13 inputs (D0..D7)
The problem could also be from the selection entries (S0..S2), either from deffective U13 or a bad adressing from the 6845, but I doubt for this option, because the ouput will be not always to "1".

So, I'm quite sure that the issue is on the D0/D7 lines, at U13 inputs.

Check with an ohmmeter, the continuity of the D0 (and D7) lines :
- check between pin 1 of U13 and pin 11 of U4 (D0)
- check between pin 8 of U13 and pin 19 of U4 (D7)
If none of thoses lines are broken, this mean that the culprit is the U13 itself, and thus, replace the 74HCT354.

#11 6 months ago
Quoted from noflip95:

OK, looking at your pictures and as you replace the U4 RAM (considered as safe), the issue should be in the U13 area.
On the pictures, you can notice that 1 pixel on 8 in permanently lighted.
The first 7 pixels are ok, and the last 8th is always lighted.
On the video board, the datas are addressed by the 6845 CRTC from the memory (this chip don't care about the data itself, and is used only for addressing the video RAM). Basically, the datas are serialized/clocked and sent to the display using the RDATA/RCLK signals. The data to be transmitted to the display are selected by U13. This chip is a "data multiplexer" and select one bit among eight bits. The address is given by MA0..MA2 and the source is D0..D7 from the memory:

The "Y" output reflect one of the eight entries (D0..D7) selected by the 3 bits selectors (S0..S2, aka MA0..MA2). Note also that, there is a pullup resistor (R7), so if an input is not wired, the default value at Y is "1"... so a lighted pixel. But on your board, R7 is not mounted (this resistor is not mandatory).
As there is one pixel permanently lighted, the issue is that at a time, the "data bit" is not transmitted but set to "1". As the first 7 bits are OK, and the last 8th is always 1, the culprit line should be D7 (or D0 - I'm not sure of the direction !). This may come from:
- a deffective RAM, but as you change U4, this option should be rejected
- a deffective U13, with a burned entry (D0 or D7
- a broken line at U13 inputs (D0..D7)
The problem could also be from the selection entries (S0..S2), either from deffective U13 or a bad adressing from the 6845, but I doubt for this option, because the ouput will be not always to "1".
So, I'm quite sure that the issue is on the D0/D7 lines, at U13 inputs.
Check with an ohmmeter, the continuity of the D0 (and D7) lines :
- check between pin 1 of U13 and pin 11 of U4 (D0)
- check between pin 8 of U13 and pin 19 of U4 (D7)
If none of thoses lines are broken, this mean that the culprit is the U13 itself, and thus, replace the 74HCT354.

Thanks for explaining this in so much detail. That makes sense. I looked at the schematic and saw U13 but could not figure out what it's role was. This confirms that it is actually involved in the process. I checked continuity as you suggested and both traces were OK. So I will replace U13 and see how I go.

I compared U13 on this board to U13 on another project display driver board. The only difference was the diode test for pins 18 and 19. On the current board with the lines, these two pins tested OK in diode test. However on my project board (untested and not working), these two pins give no reading. Can you verify what these pins should read in diode test against ground?

#12 6 months ago

Any change if you reseat the ribbon cable at both ends (with power OFF).

#13 6 months ago
Quoted from PinballManiac40:

Any change if you reseat the ribbon cable at both ends (with power OFF).

No. I tried a different cable, too.

1 week later
#14 6 months ago

Success! The replacement U13 arrived today so I took out the old chip, installed a socket, and installed the new U13. No more lines on the display! Working fine now. Huge thanks to noflip95 for all the help!

Promoted items from the Pinside Marketplace
1,700 (Firm)
Machine - For Sale
Dickinson, ND
$ 42.00
From: $ 50.00
Gameroom - Decorations
Pinball Art Prints
$ 4.95
Apparel - Unisex
ULEKstore
$ 35.00
Cabinet - Decals
Bright Lights Pinball
From: $ 799.00
Hardware
CPR Playfields
$ 224.99
€ 8.10
Flipper Parts
Buthamburg
$ 30.99
Lighting - Interactive
Lee's Parts
$ 11.95
Playfield - Toys/Add-ons
ULEKstore
$ 200.00
Lighting - Interactive
Professor Pinball
$ 119.95
Cabinet - Shooter Rods
Super Skill Shot Shop
$ 14.00
$ 27.99
Eproms
Matt's Basement Arcade
$ 39.95
Playfield - Toys/Add-ons
ULEKstore
$ 5.00
Cabinet - Decals
Siegecraft Electronics
$ 7,499.00
Pinball Machine
Operation Pinball
$ 4.99
Playfield - Plastics
ULEKstore

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