Enhancement : Gonbes VGA upscaling

Gonbes 8220 and C128 RGBI

I have quite a number of C64's, C128's and Amigas, but I only have one proper monitor.
New TV's really don't really work very well so off to the inter webs I went.

I've been looking at heaps of projects for RGBI conversion for the C128.  None really took my fancy until I saw this one from Mattis Lind, it was small, it was compact and it was surface mount.

• https://github.com/MattisLind/CGA-RGBI-to-Analog-RGB

The only thing I didn't like about it was the connections.  I'd rather have them on board than solder wires on to the board.  Luckily it's opensource and the Tool Mattis used was probably the easiest PCB design tool I've ever tried ( I've given up on every other one ).

So I added in some bits including mounting holes. I did make one mistake and that was to break the ground.  I used a jumper to fix that with the original holes for the wires that I left in place.

 As you can see the over all result was really neat with all of the colours displaying nicely.

Gonbes 8220 and Amiga RGB

I also wanted to get my Amiga's working nicely on a monitor too and not the TV I was using.  The colours were really washed out.  The pin out on my Amiga monitor cable was not compatible with the RGBI board.  However I was able to use it a as template to build a nice connector to the Gonbes unit on a bare RBGI card PCB ( note it's just point to point wires and a resistor, nothing else ).

Details for the hook up came from this link

• https://ianstedman.wordpress.com/2015/01/25/gbs-82xx-experiments-part-2/

Which I found under this video

• https://www.youtube.com/watch?v=xqlrOcGZx38

 As you can see the results are pretty good.  

(The monitor I used to test was really crappy)

 

Comparing the Amiga Board to the C128 Board.

Repair : C128 PSU working ( but was DOA ).

I've done a lot of reading about how crap the Epoxy filled c64 power supplies are ( do not use them, put them in the bin ).  Everyone however seems to agree that the c128 power supplies are great and worth using.  I never got a power supply with either of my c128 so I thought I'd get one.

Off to Ebay I go and get a "working" unit . . . yeah right.  When it arrives it's totally dead.  I have a look inside and the Caps have leaked and one of the fuses is in parts.  On further inspection BOTH fuses have not survived the bumpy ride to Northern Australia and to add to that the 1.4A fuse was only 1A . . . Hmmm . . .

That's cool, I can fix this and I was planning on re-capping it anyhow.

Here is the unit after I gave it a first initial clean and flushed the entire board.

You can still see some gunk around the 4th diode and where the resistor and the two wires join.  I used a desoldering gun to remove both of the caps and then used an interdental brush to make sure it was all as clean as possible before flushing the board again.

Desoldering guns are awesome, so after 5 seconds the Old caps are out and the New ones are in.
They are not exactly the same voltage spec, but the uF is exact.  You can go higher with the voltage without an issue ( just don't go lower ).  They are also good quality Panasonic ones.  Don't buy cheap caps.

 

Back it all goes into the case, I'm not turning this on until everything is in it's correct place.

During transport this tab broke off.  A little Tamiya liquid cement and you can't even tell it was broken.

At this point I've taken it outside and plugged it in with extra an extra RCD just to make sure the magic smoke didn't escape.  After a good run I tested the voltages, which ended up being 10V AC and 4.9V DC.  I'm pretty happy with that so on to the final phase.

 

 Plugging it into my secondary C128 and hey presto.

There's only one thing to do now and that's to replace the plug with so I don't need a travel adapter.

Repair : Amiga 600 for parts, not working ( corroded trace )

Due to my geographic location, local population and transient demographics it is really difficult to get reasonably priced Amiga kit.  Working Amigas are like gold.  So the cheapest solution I have is unfortunately Ebay and "For parts, Not working".

So far I have bought two "For parts, not working" Amiga 600's.

Amiga 600 number 1

The first Amiga I got came all the way from the UK,  It was grubby but overall it was in good condition.  Opening the case it was clean, the caps have not leaked ( yet! ) and it looked in really good shape overall on first inspection.

Powering it up told a completely different story.  The screen flashed from grey to green.  I hit up Google and found this wonderful resource.

http://wiki.classicamiga.com/Amiga_boot_error_code_colours

Seems like I had an error in the Chip Ram.  Initially I thought I'd have to recap it first, but then I noticed a little fuzzy blue coloured dot near the RAM.

One of the traces to the RAM had corroded into a blue copper oxide puff ball.  I cleaned it with some Isocol and a cotton bud and found the trace has completely disappeared.  Using a multi-meter I tested all of the surrounding traces and found only one was broken.

A little soldering and some wire and hey presto, a fully functional Amiga 600.

Update : the other corroded trace also finally gave up so I've bypassed that one as well.  It was pretty bad before I cleaned it up.  This time I scraped all of the bad traces off of the PCB.

Repair : 1571 Power supply issues

When I bought my C128s I really wanted to get the floppy drive that was designed for it.  So I bought a 1571.  Like most retro gear it was sold as working, but there were . . . problems.

The drive would power up but not stay on once the disk was being accessed and it would reset.  The problem was obvious bad power supply.

Back to Google I go and I found the wonderful blog World of Jani with what I needed.

http://blog.worldofjani.com/?p=2131

I wasn't too keen on the original bare power supply or trying to fix it.  I wasn't able to get that model mentioned in Jani's blog either.  In the end I picked up another caged Mean Well power supply from RS components and set to work.

STOP . . . These voltages will, KILL YOU . . . STOP

I don't recommend doing this at all, mains voltage is really dangerous.
Get someone qualified to do it for you.

This is the unit I ended up ordering and installing :

https://au.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/6447073/?sra=pstk

Now I have a beautifully functional 1571.

Repair : Bad C64 Colour RAM

One of my first C64C Ebay purchases was a complete "working" C64C with a 1541II and a number of games.

When I got it, it was great but it just looked washed out.  It wasn't until I tried a few more games that I realized that something was actually wrong.

. . .

To the Internet

. . .

Everything we need these days is a quick search on Google.  I found two fantastic site right away.

Ray Carlsen's amazing website : http://personalpages.tds.net/~rcarlsen/

Pictorial C64 Fault Guide website : https://derbian.webs.com/c64diag/

The first thing I did was order a C64 power supply from Ray.  I really did not want to damage my C64 any further.

The second thing I did was buy a cheap desoldering gun and some DIP sockets.  Get the right tools and do it right the first time.

The last thing I did was get a couple of colour RAM chips.

. . .

So the process was pretty simple.

Add a little solder and use the desoldering gun to free all of the pins
Use some solder wick to remove the remaining solder with your soldering iron.
Solder on a DIP socket ( always put in a socket . . . always ).
Push the chip in.

Behold . . . real colour . . .