Yves M has joined the site so expect even more repair log goodness soon.
Welcome Yves M!
Aug 292015
Aug 292015
As Ive mentioned in my repair log of the Fluke 90 there is some useful functionality that is only available when connected to a PC.
These features appeal to me but I dont have an old PC lying around in order to use the ancient DOS program for this so I made my own.
What I do have is an RS232 to USB converter so I removed the DB25 connector and changed it for a standard 9 pin variety.
With that made up I could quickly test it was correct by firing up a terminal window and sending any command. If successful the Fluke will display “REMOTE” on the LCD.
Here is the software I have been working on the last couple of days.
Here it is all connected up to Breywood and working
Its not finished yet and certain things will be tweaked and changed and added in time but I successfully tested it today and almost everything works great.
I still need to work on the UPLOAD and DOWNLOAD functionality but the tracing works fine which is what I was most interested in.
I cant imagine many/any people wanting this program but here it is anyway. It should be compatible with all the Fluke 90 devices. There are some CPU specific commands here which are included despite the fact I cannot test them.
It requires .NET 3.5 and should work on both 32bit and 64bit machines. Available in the ‘DOWNLOADS/SOFTWARE’ section
HAL21 repair log
PCB Repair Logs, Repair Logs
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Aug 272015
Got this HAL21 PCB from my frend Josef for a repair.The game is a vertical shoot ’em up produced by SNK in 1985, a mix between Xevious, Terra Cresta and Alcon.
Board was in good shape given its age:
but fautly since it didn’t boot at all, stuck on a static garbage screen:
First thing I noticed (besides the fact that it didn’t boot) was the wrong colors, specifically the red one was missing. My friend Josef gave me an hint pointing me to a missing transistor 2SC1815 @Q1 near the edge connector:
Actually this transistor was for driving the RED ouput (the other two are for BLUE and GREEN) so replacing it restored correct colors:
So, I started my real troubleshooting .Hardware is made of two Z80 CPUs ( a main and sub one) plus a third one for the sound.I decided to hook up my Fluke 9010A in order to perform some test on main CPU.MAME source reports this memory map for the RAMs:
AM_RANGE(0xe000, 0xe7ff) AM_RAM AM_SHARE(“spriteram”) // + work ram
AM_RANGE(0xe800, 0xf7ff) AM_RAM_WRITE(marvins_bg_videoram_w) AM_SHARE(“bg_videoram”)
AM_RANGE(0xf800, 0xffff) AM_RAM_WRITE(snk_tx_videoram_w) AM_SHARE(“tx_videoram”) // + work RAM
When I performed a long RAM test on the first and third address spaces, I get an R/W error from Fluke 9010A.With the help of its probe, I could located the involved chips, eight 2114 of video board:
I probed them with my BK Precision 560A in-circuit tester which reported bad devices for the four ones on the right :
I took this result with reservations, most likely not all four chips were bad but one certainly and this affected the other ones (due the fact they share same address bus) misleading the tester.Not being able to accurately identify the faulty chips I desoldered all the four and I found two bad ones @6L and 7L:
With two good 2114 RAMs fitted, the board properly booted with no further issues.Mission accomplished.
Aug 252015
Got this Sunset Riders PCB always in a trade with my friend Ifog:
Board was really in mint condition but, as my friend warned me, it was faulty.
Actually when I first powered it up it played perfectly but after some minutes it showed an issue where some parts of graphics had wrong colors (pinkish, I’d say) :
Since I have repaired other similar Konami boards with same issue, I already knew where start to look at.Palette RAMs are two 2018 devices @13D and 14D:
I probed them with my oscilloscope but didn’t notice anything abnormal (though they were hot at touch), also piggybacking them didn’t change anything.So, I went more ahead in the palette circuitry following the path of the data bits of these RAMs.Just before the generation of the three RGB colors there are some open-collector buffers (74LS07):
Probing the one @8C with my scope, I found discrepancies between input pin 3 and output pin 4:
Once desoldered, the IC failed on pin 4 indeed:
Comparing on a tracer the bad output with a good one, you can see how the internal junction was altered (good one on the left of the below picture):
Fitted a good IC fixed the colors.
Success!
PAL dumps update
PAL Updates
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Aug 232015
Today we can record some PAL dumps.
Layer sent in a handcrafted ‘WL22B’ @1A PAL to use with the japanese 88622B-3 B-board of Willow (Capcom CPS1 hardware).
This PAL is not yet dumped and not in Mame.
Charles MacDonald uploaded on MAME D.U. mailing list the PAL dumps from an Aqua stage PCB, only the one labeled ‘315-5801’ was fully combinatorial, all the remaining were partially registered.
Lastly, always from MAME D.U. mailing list, we had a dump from an Atari Quantum PCB.Original one was from a 82S153 device @1B stamped ‘CF2038N’ (reported by Atari as ‘137290-001’) but I recompiled its equations into a GAL16V8.
All these dumps have been succesfully tested except for the Aqua Stage one.Thanks to respective people for their contributions.