Black Screen

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By Grauw

Enlighted (7354)

Grauw's picture

14-03-2018, 00:04

cobracon2 wrote:

Well at least the memory is on the main board, but my desoldering skills are lacking. Looks like I will have to practice on something else first.

Is the TMS4116-15nl memory chip a must match part? or can I use another brand as a replacement?

Since I reckon you’re going to have to do some desoldering at some point anyway, for desoldering on a budget you need a desoldering pump, solder wick is also recommended, and a bit of patience and practice Smile.

For the TMS4116, there are other compatible parts afaik, both of the same type from different brands as well as similar types which can also work. The topic was discussed recently here. I think you can also find them fairly easily on eBay or in scrap hardware from the 80s. But maybe someone more knowledgeable on this topic can answer properly, I’m just an amateur with hardware who’s by now read enough threads and messed around enough to have a little bit of a clue ;p.

By cobracon2

Rookie (31)

cobracon2's picture

14-03-2018, 00:09

Well I just power up the unit for about 3 minutes. The ls chips and the ram remained cool. BUT the TMS9118 chip was getting pretty hot. Do these chips normally run hot?

By Grauw

Enlighted (7354)

Grauw's picture

14-03-2018, 15:27

I hope someone else can answer... Since I don’t have much experience feeling VDP temperatures, much less TMS9118, I can’t say whether that’s abnormal or not.

But speculating; I would expect the VDP to get reasonable warm over time, in some machines they are fitted with a little heat dissipation plate after all, but if it gets pretty hot in just a few minutes, that’s a bit suspicious to me, not sure if that’s normal. A broken VDP could definitely cause the symptoms you describe, but so could a broken CPU, ROM or RAM. I think it is unlikely at this point that the VRAM (the TMS4116 chips) is the problem.

Did you also manage to feel the temperature of the CPU and RAM on the CPU board?

By cobracon2

Rookie (31)

cobracon2's picture

14-03-2018, 19:37

No I cant squeeze my finger in there. I will have to find my ir temp gun.

By Grauw

Enlighted (7354)

Grauw's picture

14-03-2018, 22:59

Oh, you have one of those! Fancy! Should be able to provide clues I think, or at least an interesting picture to look at Smile.

By cobracon2

Rookie (31)

cobracon2's picture

15-03-2018, 22:20

Alright I will dig it out and let it run for 5 minutes before taking the temps. Now to find the darn thing lol.

By gdx

Prophet (2207)

gdx's picture

16-03-2018, 09:50

Check if the ceramic capacitors do not touch the straps.
Check all the welds, this MSX is very old.

By cobracon2

Rookie (31)

cobracon2's picture

18-03-2018, 02:42

Yeah I plan on doing that this week. I've been so busy that I haven't had anytime to work on it. Being sick doesn't help either.

By cobracon2

Rookie (31)

cobracon2's picture

19-03-2018, 21:52

Well I finally found my temp gun and here is the findings:

All ls chips 79F
PD780c1 CPU: 91F
Sound Chip: 92F
TMS9118NL: 98.7F
TMS4116: 92F

These values are after running for about 30 minutes

Any ideas?

By Manuel

Ascended (14558)

Manuel's picture

19-03-2018, 21:59

F?

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