Space Invaders Multigame "Bit: Failed"

[HudsonArcade]

Here's the link I found thats says 3 board with CV ROM set usually works without the chip:

I stand corrected... I just disassembled and poked through the SICV ROM set, and it doesn't write to or read from the ports associated with the MB14241.
Might have to dig into it some more.

 

[HudsonArcade]

I stand corrected... I just disassembled and poked through the SICV ROM set, and it doesn't write to or read from the ports associated with the MB14241.
Might have to dig into it some more.

Found the shift code... it's quite smart -- uses repeated 16 bit adds to implement the shifts instead of doing 'normal' bit shifting operations.
It's still slower than the hardware shifters, so it'd be interesting to run the ROMs side by side and see if the game plays slower.



(Note: This is in Z80 syntax not 8080 syntax, since I find it easier to read)

 

[wugly]

regarding the replacement chip. doesn't the sound board sit at the very top of the cage and if you added another socket or machine pins between the socket and the fabricated chip replacement board would you then have the space to put it all back together and have the replacement chip hang outside of the cage.

on my 3 board b/w taito board I have a metal plate on the bottom rail. then the rom board on the next rail and then the cpu board on the top rail. the sound board is connected to the cpu board with plastic spacers and is not in the cage itself

 

[JoeB1355]

regarding the replacement chip. doesn't the sound board sit at the very top of the cage and if you added another socket or machine pins between the socket and the fabricated chip replacement board would you then have the space to put it all back together and have the replacement chip hang outside of the cage.

on my 3 board b/w taito board I have a metal plate on the bottom rail. then the rom board on the next rail and then the cpu board on the top rail. the sound board is connected to the cpu board with plastic spacers and is not in the cage itself

Yep -- Couple posts back I realized the same thing. Don't think I need the socket for height it was more the overhang, but then I realized it was actually "outside" the cage.

I did use an extra socket for the multi-kit though to clear all the caps.

 

[TONYUK]

Hi started a new tread on this and then realised this has already been discussed before, sorry for duplication but haven't had any pick up on the new tread and I really could do with the advise.

I have a Midway 1978 upright Space Invaders. Owned it for decades but it went down just before going into storage when we were having the house extended. Now out of storage I had to do a few repairs first as before I owned it someone had soldered the main board connectors making it difficult to service, however sorted that and checked the power supply etc. which resolved most of the problems , however the invaders appears as a single block (see attached) and I am missing the invader hit sound.

Purchased a Braze Kit & RAM tests fine but indicates BIT FAIL and confirms invader hit missing on test. I have a cocktail board & replacing the original daughter board with cocktail board the graphics are fine but I have only one sound. Before I tinker with the cocktail board I would like to sort the original board so I started with the bit shifter related to the Invader Hit - No Change and then worked my way through the rest. It should have been the bit shifters as balloon bomber and all the other games available on the braze kit that don't use the bit shifters work fine
I have now replaced all the 25S10 bit shifter chips, 74174 at C5-E5, 7417 F5, LM3900 at M4 & M5, 556 at H4, 7442 at E5, 74153 at A3 to D3 & all electrolytic caps. The image probably a little sharper still but no Invader Hit sound and square white block instead of invaders..
My next target is is the 7411 at H2 but I am beginning to think I am barking up the wrong tree, HELP!

 

[wugly]

you are going to need a logic probe. you are going to have to look to make sure you are getting activity on the data lines and port5 on e5 then look to see if you have output on e5

regarding shifter are you getting pulseing on pins 9 10 13 on the 25sio chips

 

[TONYUK]

I will take a look and get back to you, bit awkward I haven't go the space for full bench test set up so I am doing this on the machine which means crawling under a pinball machine.
One question, my schematic shows pins 13 not used on the 25S10 chips?

 

[TONYUK]

Port 5 E5 I am getting Low

My mistake (in a hurry) pin 13 on 25S10s tied to A5 - 74175

A4
9 = NO SIGNAL
10 = Low,
13 = High

B4
9 = Low
10 = Low,
13 = High

C4
9 = Low
10 = Low,
13 = High

D4
9 = Low
10 = Low,
13 = High

 

[TONYUK]

Board out and looks like I have a bad connection at pin 9 - A4. I will have to solder jump in tomorrow UK time and see if that sorts anything.

 

[wugly]

are you sure my schematic has 13 9 and 10 being used for controlling the 25s10 its fed from the 74175 chip

Board out and looks like I have a bad connection at pin 9 - A4. I will have to solder jump in tomorrow UK time and see if that sorts anything.

good catch. as you can see just changeing chips has a flaw. don't think that the one fault on soldering is the only one on the chips you replaced

 

[TONYUK]

Sorry got distracted by Space Laser which works fine as does every other game on the braze kit except space invaders and space invaders deluxe but having fixed track to pin 9 which is now intermittently pulsing, no apparent change still no invader hit and invaders still appear as a block, interestingly on space invaders deluxe the invaders are almost correct when they load from the top of the screen but every other step appearing as a block but turn into a solid block when the game starts proper, also some white blocking in score line but when the saucer appears it clears the path Infront of it but when the character comes out of the side of the screen to turn the inverted 'Y' the correct way up in the title sequence it comes out as a white block.

I am going to whip the board out again, I did check the tracks and connections when I changed the chips but clearly on A4 the track repair I had previously done was not good enough but you would have thought by now I would have resolved either the sound or graphics issue or generated another fault but even with PIN 9 not connected the game was playing the same as it is now with the track sorted!

 

[wugly]

is the tant cap in the saucer hit shorted? double check the chips you already replaced and you might want to check the 153 a3-d3 which passes back data

 

[TONYUK]

PROBLEMS SORTED !!!!

Blinddog 2 replied to my earlier post and suggested that the schematics are miss labelled and to try K4 and K5 and yes invader hit LM3900 @K5 not M4/M5

Graphics 74175 @A5 it was on my list but to be fair there wasn't much to go, just hoping it wasn't anything to do with 76477 @H2 as this is the only chip I don't have spares of.

Thanks for the help. Trying to decide if I have the strength to sort out the sound on my alternative cocktail board now.

 

[mystery_base]

My newest design is going off to the fab soon:

View attachment 498511

Are these substitute boards available? Can you point me to them? I am in need of the bit shifter for my restoration, though solutions like these are wonderful and should be supported.

 

[HudsonArcade]

Are these substitute boards available? Can you point me to them? I am in need of the bit shifter for my restoration, though solutions like these are wonderful and should be supported.

Work got busy and these never got made.

 

[mystery_base]

thank you for the update

 

[philsfan64]

Old thread, I had the same error today. I turned it off and back on and the error cleared. I suspect it will come back.

 

[philsfan64]

I've gotten this bit shift failed error several times now but I don't see any issues with the game play. It seems to be working fine. What should I be looking for?