by bassybeats | Jul 24, 2022 | Retro Gaming
Another $50 grab, except this time it was 2x JVC PVM’s and a little 9″ Pelco PVM. All in unknown condition. Other than I was told the RGB one turned on but the colours were all awful and probably needed a recap.
So, whats wrong with it?
The first few things I noticed was that externally the unit had a rough life, scratched up and engraved with two of the rear BNC connectors bent in. Other than that, it looked okay. Once I dug into it is was clear this thing had ALOT of hours on it, no burn in but everything was covered in black soot. So the first step was to strip the whole thing down and clean everything in the sink with soapy water and leave it for a week before re-assembling everything.
Thankfully, the strange tearing at the top of the screen went away after cleaning everything and reassembling and I replaced the BNC connectors with new ones while it was all apart.
Colour bar calibration
Now to get to that strange colour issue. At first I thought it was bad caps but after dialing in the colour bar test it was clear that the drives for the guns were bad, the micro trim pots up front had been messed with and it just needed a really good calibration. So I started by centering all the front adjustments, both the trim pots and the main controls. Then I brought up a solid white picture on the tester and adjusted all the gun drives until I got as white of a picture as I could. Once I had done that I brought up the colour bars again and used my LCD with the same image as reference to match them as close as possible.
After that, it was just a matter of playing some familiar content and adjusting up front to get it how I would expect it to look, Sonic 2 being the best for it.
Looking good
I then put it through its paces over Component with some Batman The Animated Series, Dragonball Z, Iron Maiden DVD’s, Rachet and Clank and Portal 2. This thing is starting to look great. It still has a slight red tint I need to dial out of it but I kind of need two people as it is all manual controls and it is hard to adjust at the back and look at the front.
by bassybeats | Jul 24, 2022 | Retro Gaming
Another great score with the Sony 1440QM PVM. A 14″ Scart/RGB CRT that is perfect for gaming, only problem is its a little bit unwell.
Assessing the Condition
For a $50 pickup its in better condition than I was expecting, It did not power on at first but I was told that it was disassembled and it was attempted to be ‘recapped’ to fix a different issue. Upon opening it up the no power issue was attributed to a connector not being plugged in ( the red ribbon cable going to the front panel ). Once plugged back in, the unit fired into life, albeit with the symptoms I was told it had which was a deflection collapse at the top and purity issues.
Diagnosis
Somehow, I made it worse. By disassembling and reassembling the unit I managed to kill the front panel. Somehow I killed the 12V regulator that was going to it, so after swapping the 7812 regulator I was back to where I was the first time around. While I had it apart I did some checking and testing and couldn’t see anything apparently wrong. After a lot of googling I found the same issue I was having, but in a different model. The issue is called “Horizontal Line Fold-Over” and it caused by, you guess it, bad caps. The caps weren’t the same in my unit but I could at least match up the areas on the main boards and start there.
Recapping
I decided, while I had the whole thing apart that I would recap the entire vertical deflection section ( the problem area ). I had all but two in stock and tested them as I pulled them out. A lot of the high voltage caps were toast, caused by sitting next to very hot resistors and transistors. Once I had done the recap, I reassembled the unit and put fresh grease around the anode cap.
Calibration
Now that the vertical lines were all gone it was time to calibrate the display. The purity issues were temporarily fixed with some permanent magnets siliconed onto the frame until I can find some purity magnet strips. As for the rest, I just spent an hour or so with the Mega Drive 240p Test Suite and adjusted all the trim pots ( no on screen display in this thing! ) and then carefully adjusted the convergence rings until it I got it as close as I could by eye. Someone else with more experience could get it better but its 100 times better than where I started from.
Working, finally
Lots of calibration later and the unit is finally in working and usable condition. There is still a bit of work to do, namely the purity strips and the finding a Sony badge for the front. All in all, not a bad score for $50!
by bassybeats | Jul 24, 2022 | Computing
This Willem Eprom Programmer V4.5 build should have been an easy one but it turns out, when you have the wrong parts without knowing it, it turns into a much harder job.
Building the unit
Most of this build was fairly straight forward other than I had to swap the ZIFF socket out as it was cracked right through the middle. Some of the parts were not easy to find and I had to get them through a friend from mouser like the CD4503 and the CD4015’s.
The never ending Parallel Cable fun
My choice to use a parallel/db25 extension cable would come back to haunt me. I tried using a gender changer adapter to get it to work but no matter what I did, it would just not detect it on the PC. I soon found out that the ‘Parallel extension’ cable I had purchased was actually a DB25 serial cable and not all the pins were actually wired. Once I had desoldered the connector, put on a female DB25 connector on the board and used a different fully wired cable, the device sprang into life!. So a word of warning, make sure the cables have all pins wired up.
Another thing to check, is that you need to use the right version of the software. For the V4.5 board, I used the 0.97ja.
by bassybeats | Jul 24, 2022 | Computing
This was an odd pickup where the machine had a cracked screen AND a dead SSD, so the only way to replace the SSD was to also replace the screen. Which I found out was not a very fun job.
Ordering the screen
I scored a new to me screen on Trademe for $10 and when it arrived it was apparent that the touch screen ribbon cable had been severed during the removal process by the previous owner. So I ended up removing the touch screen module and just turning this Surface Pro 3 into a regular tablet.
The Guts
The Surface Pro 3 uses an annoying mSATA m.2 drive which are far less common in 2021 So I had to troll trademe and marketplace to find something. I scored a $25 64gb drive that was smaller than the stock one but would at least get this machine back into a working state.
Installing the OS
For whatever reason, Windows 10 was just extremely slow on this machine. I’m not sure if its an issue with the new SSD or what but it was fine with Linux so I just stuck with that. Linux Mint was, as usual the OS of choice.
by bassybeats | Feb 8, 2022 | Computing, Retro Gaming
Starting DOS 6.22 image
This was a very long running project that started off with a Direct Access 5 based DOS 6.22 image from my mate with a fairly stock install with some utilities and games loaded on it with a bunch of sound card drivers. This image was targeting a 512mb compact flash card size. I really wanted to ‘max’ out the stock DOS 6.22/FAT16 partition size of 2GB so I had to start again.
Software Selection
To make the most of the 2GB CF card size I had to compile a list and collection of games, utilities, demos and programs. I opted to exclude CD based games as they are too big and getting virtual CD iso’s working is not an easy task.
Base Image
To get the image prepped, I did a clean install of DOS 6.22 onto a 2GB CF Card and then ported over my mates files to it. The base machine it was built on was a DX4-100 486 machine with 32mb ram, Sound Blaster 16, dual floppy, cd drive and XTIDE card.
Once that was done I added the DOS menu from Phils Computer Lab also adding his autoexec.bat and config.sys. After that, I imaged the cf card so I had a backup incase I messed it up while building it out. Something to take note, not all CF cards are made equal and you need to take note of the image size. I had to make 2 images in the end as one card was 2048mb and the other 2079, so the larger image won’t fit on the smaller card if you want to duplicate the image to more cards.
Menu Structure
I tried to split the main menu structure up into obvious and easily identifiable areas. Going from:
Windows 3.1, Configuration tools, File Management, Graphics and Audio software, Phils Computer Lab benchmarks, Action Games, Adventure Games, Beat’em Up games, Fighting Games, Flying Games, Platformers, Puzzle Games, Racing Games, RPG’s, Shooters, RTS Games, Simulators, System Information, Programming Tools, Office Apps, Diagnostics, Utilities, Demo Scene stuff, Launch Box and Emulators.
Menu Configuration
As for the menu configuration I decided to remove the Direct Access boot screen and have it go directly to the menu and added a little 2001 Space Odyssey reference with a red and black theme.
The folder structure on the CF card mimics the menu structure with the exception of the folder and file names as they have a 8 character limit before the do the ~1 thing. Within the sub menu’s, its just a matter of manually typing out the menu items, navigating to the folder and launch exe or bat file. For bat files, you have to type BATCH in front of the file name to get it to launch. For Windows 3.1 applications or games you have to type WIN in front of the filename. You can parse through commands using the custom option in the menu, this lets you CD into a directory or set parameters on the exe file for example, this is how I setup the floppy disk tests and other options in the configuration and diagnostic menus.
Its all Working
After ALOT of testing, I got all games and apps launching. Some of the big hurdles were getting the WIN command to parse through ( needed to set some settings in the config.sys/autoexec ), getting the BLASTER settings right, getting the C64 emulator working with games, getting the Apple II emulator working. I ended up dropping a lot of apps due to them needing the cd or having multi floppy installs or just wouldn’t install. Some games I dropped due to them being unexciting or glitchy. Planet X2, Commander Keen and Doom were my go to test games for sound and graphics.
Some creature comforts I added were the TAB auto complete function and command history function from FreeDOS as well as the mouse drivers.
Just to be cautious, I imaged it at this stage onto my NAS so I couldn’t screw it up. I also removed a couple of things and ported it to the smaller 2049mb CF card as well.
FreeDOS attempt
Once I had the main DOS 6.22 working I did a clean FreeDOS install on a new CF Card and moved over the files, which proved to be extremely annoying with floppy installs constantly failing and CD installs locking up. I ended up using the R2 version that worked a treat first time. I had to replace the boot menu, autoexec and config.sys but it basically just worked, EXCEPT that Windows 3.1 basically doesn’t work with the FreeDOS memory manager. After a couple of days trying to get it working I ended up giving up. This was intended to be my FAT32 version of this build.
Future Ideas
Something that I would like to get going is CD ISO emulation on a larger drive using DOS 7.1 or FreeDOS. But I just had no luck getting it to work, and CD ISO emulation has the limitation of no CD audio.
I’d also like to try find a way to have sound card options that were switchable from a menu. Something like, run a batch file that comments out the Soundblaster settings and uncomments the gavis audio ones and visa versa. But DOS command line fu is not strong enough.
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