Burned-out HB-F1XDJ

Por Louthrax

Prophet (2249)

imagem de Louthrax

29-04-2019, 00:48

Hi all,

Seems my good old HB-F1XDJ has been victim of a burn-out this week-end: I did not pay attention and let him powered-on during 2 whole days. That was too much for him.

Now, when I power it on, the screen is OK for 1s, and then it quickly dims to black, and remains black... Other things are still operationnal (CPU, drives, sound), but the display is black.

I changed all the main-board capacitors a while ago, but did not change the daughter-board ones (like advised here).

I have not investigated anything so far, but does anybody have an idea of the things to check in this case, or knows which part of the computer is responsible for the video output processing/amplification ?

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Por sd_snatcher

Prophet (3257)

imagem de sd_snatcher

29-04-2019, 01:00

Hi Louthrax!

You should replace the capacitors of the HIC-1 PCB ASAP! That's exactly the part that does the video output processing/amplification, and the symptoms of your machine point that those dangerous capacitors are going bad.

On the mobo, the only capacitors you really need to change are those of the FM circuit, as recommended in MSXpro's maintenance guide. I've seen people replacing the other elcaps of the mobo with new ones, only to seem them leaking a few years later because they were either Chinese, or fake capacitors.

Por Louthrax

Prophet (2249)

imagem de Louthrax

01-05-2019, 18:49

Hi Snatcher,

Thanks for confirming the cause of the problem. I finally started the SMD recap operations I should have done way earlier on the daughter board (using tantalium capacitors):

And it solved the problem, I've got a super nice and sharp display again :RNFF:

The old capacitors started leaking, but just a bit (no tracks corroded). Removing them was not as hard as expected (soldering connections area are large and looked solidely attached to the PCB).

I just totally freaked-out when powering-on the F1XDJ for the first time after the re-soldering : logo was displayed in a weird way, everyhing was super-slow... But that was just because I hadn't plugged the front-panel connectors (with the speed-control and auto-fire sliders) :)

Por Louthrax

Prophet (2249)

imagem de Louthrax

22-03-2020, 22:48

And damned, it happend again today. Same symptoms as before, and probably same root cause - I again let my F1XDJ work during one full day !

After that (I did not notice the problem then), I also plugged it on a bad SCART switch/splitter (you know, the ones that do not have separate lines for RGB and probably other signals) together with another MSX video device. It was working fine for a while, until I had both the F1XDJ and the device outputing video at the same time. Screen got out of sync for 10 seconds or so before I unlpugged everything, and then the F1XDJ screen started to dim.

Could it be that the extra video signal had burnt the video amplifier capacitors ? (I do not believe in that too much, that already happened to me with other machines several times in the past with no damage) ?

Could it be the tantalium capacitors I used are crap and do not sustain one continuous day of work or the extra signal ?

Or maybe the other biggest capacitors (shown on the picture above) are now also dead ?

Let me know what you think. I'll open the machine again this week and investigate. This MSX has already been saved two times (first for FM sounds, then for screen dimming), I won't let him die like that Smile

Por sdsnatcher73

Paladin (870)

imagem de sdsnatcher73

23-03-2020, 07:09

Hey Louthrax, that sucks but good to hear you won’t let it die! I am not sure what made it die this time. I do have a picture of an F1-XD (the slightly older sibling of your F1-XDJ) which has replaced caps as well (done by Omega):

It seems he used different models (even different ratings it seems but I may be misreading it). Anyway hope it helps your search for new caps if the ones you replaced have already gone bad...

Por gdx

Prophet (3427)

imagem de gdx

23-03-2020, 09:20

You took capacitors for what voltage?

Sony chip (under the sticker) can also be the cause of the issue.

RS-232 switchers like below are cheap and efficient to make a RGB switcher.

http://www.ebay.ca/itm/Printer-DB9-Pin-Serial-RS232-Switch-M...

I use one for years.

Por sd_snatcher

Prophet (3257)

imagem de sd_snatcher

24-03-2020, 12:13

@Louthrax

Check if you were able to clear all the old capacitor goo from the HIC-1. It might still be there, corroding the daughterboard.

Use a multimeter to check all the HIC-1 video path connections too.

Por Louthrax

Prophet (2249)

imagem de Louthrax

24-03-2020, 18:04

Thanks guys. I think I'll have some free time to investigate that soon.