Tutankham : No video

[NivagSwerdna]

So it's 2024 and I really wanted to get some screen shots of the star field that is shown when Tutankham is on the "PRESS START" page...
(feel free to post some pictures of the four alternate star fields on that screen if you have a real Tutankham)... anyway...

Quite a few years ago I bought a Tutankham boardset but I have never powered it up and TBH I cannot remember if it was meant to be working or not when I bought it.. anyway...

Supplied +5, 12V and -5 to the board and all I get is a white screen. I think there might be a flicker of life before the white screen but it is very transient and may be nothing...



Not very impressive.
I checked the voltages at the corner of the one of the 4116 RAM chips and see -5V at p1, +12V at p8, +5V at p9 to GND at p16. Some of the RAM seems pretty hot.




I notice that there is an empty socket at I12... not sure if that is correct? Looks dirty so may have always been empty?



I guess I dump the ROMs as Step 0

I haven't tinkered with one of these so any suggestions as I try things will always be gratefully received.

Happy New Year!

 

[Mc-Q]

4116 dram will usually burn your fingers if it's bad
do you have a frequency counter or a multimeter/scope with one?
when i get a blank screen my first test is to check the sync pin for 15KHz

 

[NivagSwerdna]

I have a scope and logic probe.
Just working my way through the ROMs... Done the bottom row which I think are Graphic only and they are good apart from the two on the right, one is dead and one is intermittent.
Is there a diagnostic ROM for Tutankham? If there is I could burn one as I fix the dodgy ROMs.

 

[NivagSwerdna]

Removed the ROMs from rows I and H...

All read OK except for H2 which reads different each time, as does I8. I9 seems shorted in some way and will not read. Need to burn some replacements for those three.

8d2a3665db937d0e1d19300ae22277d9db61fcbc *h1.bin    tutankhms
UNSTABLE                                  h2
910718f36735f2614cda0c3a1abdfa995d82dbd2 *h3.bin    tutankhms (3a.3h)
bd10bbb413d8dd362072522e902575d819fa8336 *h4.bin    tutankhms
458ea2ff5eedaaa02e32444dd6004d2eaadbdeab *h5.bin    tutankhms
3112cf831c5b6318337e591ccb0003aeab722652 *h6.bin    tutankhms

664d3e08df0f3d6690838810b6fe273eec3b7821 *i1.bin    tutankhms
e8455eab03f66642880595cfa0e9be285bf9fad0 *i2.bin    tutankhms
683899e1014ee075b16d9d2610c3c5b5c4efedb6 *i3.bin    tutankhms
e4ab27c09858cede478f4ed3ac6d7392e383a470 *i4.bin    tutankhms
7068797770a6c42dc733b253bf6b7376eb6e071e *i5.bin    tutankhms
2a78039ee63226978544142727d00d1ccc6d2ab4 *i6.bin    tutankhms
cf10308a0fa4ffabd0deeb186b5602468028ff92 *i7.bin    tutankhms
UNSTABLE                                  i8
ELECTRICALLY DEAD                         i9

I'm tempted to UV erase and re-burn them all?

 

[Mc-Q]

i always erase and re-program eproms.
i also sometimes do it with gals.
you need to remember the bits are tiny capacitors - eventually the charge disipates.
we already get over twice the life in the datasheets from them!
most datasheets say data-retention is 10 years

as for diagnostics - there are a few konami ones - i wonder if they have sourcecode with them.

 

[Mc-Q]

this is my second favourite konami game btw - after juno first.
so you must fix it on principle

 

[NivagSwerdna]

Removed all UV EPROMs from rows I and H... Removed labels, cleaned up windows with IPA, Erased, Programmed and Verified. The one I had suspected was dead went in the bin, 3 didn't seem to verify reliably so they are now marked as suspect. Replaced the 4 problem ones with some from my small 2732 stock, re-ordered some more from China.




Contact cleaner on the single wipe sockets and formed the legs to the right spacing with my cheapo plastic IC Straightener Tool
Applied power...





and...



Another disappointingly easy repair!
Actually I only need this so I can see the Star Field since I am looking at reversing the Konami 084, so I don't need to investigate much further but it's nice it is working when I put it back in the box.

PS
If I was being critical I would say the background is not completely black but showing some noise... might need to investigate the final video stages at some point.

 

[Mc-Q]

nice.
i usually replace those bakelite sockets.
i also usually replace licensed romsets with japanese ones
because we all know "Winners DO Use Drugs" and nobody wants an FBI splash screen on their game.
besides, sometimes the japanese roms have more intro's or gameplay in them!