Test Bench cont

Jamma Wiring.

With the monitor in place it was time to add some of the wiring and the power supply, so it would give me an idea of where i needed to fit other stuff on the bench, as i didnt want it to look clutter'd.
First thing i did was take my old test rig (which i built years ago) and rob it of bits. So i took the jamma power supply, which is a rare one as it has -12 volts too. The jamma edge connector and loom, but as i'm going to fit a separate speaker to the bench, i didnt bother with the low level audio converter. I sat my scope in place so i had an idea what space it left me and it worked out i could sit the jamma PSU next to it.

Power supply & Isolation transfomer.

Once i had the PSU in place i could work out where i was going to put the Isolation transfomer (which i had robbed from an old jamma cab) and where all the wiring would need to go for the RGB and power outlets for when i need to test and work on monitors. Luckily i knew the iso transformer had been powering a Hantarex 9000 monitor in the past, so i dug out the manual for this model and wired it accordingly. What i also had to bear in mind, is that Hantarex changed their RGB wiring between certain models and swopped the position of the RED and BLUE wires on the chasis connector, rather than make life complicated, i decided to do the mods when i make adapter looms, so each loom that plugs in the front will be for what ever monitor i.e. Hantarex 9000, Hantarex polo, Wells Gardner etc...

Chasis position.

With all the power wiring sorted, it gave me a chance to work out where i would put the monitor chasis and considering i still had to allow for the Jamma edge connector, i decided to put the chasis on the right hand side, which would still leave me space for a speaker, credit button and 1 and 2 player start buttons.
At this point, i also added 4 small 3" bits of batten to the wall to act as support points for the lid, which i also cut from the kitchen worktop. Rather than attatch this with the 90 degree fixings, i opted for magnetic latches, which would hold it in place securely, but at any point i could remove with ease, should i need accesss.

Connectors for jamma, RGB.
I fitted a 9 pin D plug socket and wired it to the RGB, GND and Sync outputs from the jamma loom.
I then drilled a 8mm hole about an inch and a half below this D plug and wired up a male D plug for RGB, GND and Sync threaded the wires through the hole and connected this to the chasis for the test rig monitor. This means i can leave it connected when using the test rig and then unplug it and use patch leads to hook up to any monitors i want to bench test.
Below this i fitted the jamma edge connector and either side of this i fitted LED's a GREEN one on the left as a 5V DC indicator and a RED one on the right as a 12V DC indicator.

Adjustments for RGB.

Again to make things as versitile as possible, i decided to add RGB level cut offs, so that i could fine tune any image on the test bench monitor, as aging game pcb's all give out different levels of video. By having these, it will save me having to take off the top of the bench and fiddling with the neck card pots.

These are just 10K pots, i also bought rubber knobs (colour coded RGB) to make the job nice and tidy, as a finishing touch i also added some letterset.

(Pots and rubber knobs, sourced from Maplins )

Monitor chasis re-build.

It was then time to look at getting the 10" monitor working and so i needed to souce a few bits. Craig (Ordyne) another member from #Jamma+ forums and also the owner of Giz10p games supplied me with all the parts i needed to rebuild the 10" Hantarex chasis, all at very good prices too....

A brand new line output transformer (LOPT) a chasis Cap kit (decent panasonic ones) and a scrap 9000 chasis that i could rob missing parts off (transistors, resistors etc..)

Monitor chasis re-build cont.

I started by re-capping the chasis first (handy having a de-soldering station, makes light work of removing things on mass), then i replaced all the missing components and finally finished off by fitting the new line output transformer. Doing all this should of given me a nice clean and crisp picture, but when starting her up for the first time, it became apparant that something wasn't working and there was no glow from the heater in the neck of the tube. So it was time to source a new tube and luckily enough a guy was selling Playchoice 10 bits on ebay, so i emailed him and asked him if he had the 10" monitor and he said yes but it didnt work, so i bought this off him and swopped the tube from it into the bench but used the chasis i had rebuilt and bingo !!!!

Up and running.

Click banner for home