TI-99/4a Modification Weekend.

[Sinphaltimus]

 

No, you need to measure it out of circuit. Switch off the PEB, pull the resistor wires off those two pins you added, and measure across the resistor with it not connected to anything.

so when I set my multimeter to 2k ohms I get 0.10, when I set it to 200 ohm I get 10.0 - does that mean my resistor is 10 ohms and not 10k ohms? Or better yet, what does that mean?

[Stuart]

Looks like 10 Ohms. Which is consistent with the pictures you've posted - a 10 Ohm resistor has colour bands brown-black-black-gold, and those last three bands seem to correspond with what's left on the resistor.

[Sinphaltimus]

OK, looks like I'll have to order some spares. Thanks for your help.

[Sinphaltimus]

So after measuring my resistor and ordering some spares I broke the weak connection in the corner of the board reinstalling it.

 

 

So I had to locate a new place to resolder a connection. I spotted an unused solder hole just to the left as I followed the trace.

 

 

I heated up a pin to push through the solder then clamped it into place.

 

 

Then some flux and solder - it's now secured better than before.

 

 

Now to understand what I'm up against. The solder point it on the back of the board, I am basically soldering blind - memorizing cell phone pictures to get my plan in place.

 

This is the top of the board after the work was done, the solder side is facing in towards the bottom of the PEB.

 

 

Lo and behold. It lives! it hungers!

Edited May 19, 2017 by Sinphaltimus

[digdugnate]

sweet!

[Sinphaltimus]

In the middle of the PEB there are 2 switches. One RESET which is wired to a connector on the outside. It's waiting for me to modify the console with a reset header so I can hard reset the console when needed. The older console that used to have the header still does but I have my nano and other mods applied to that one.

The power switch is actually wired to my GoTek, it's the switch that loads the disk image after I select it with the two buttons on the GoTek. The displays are the GoTek image selection display and 3 temp probes for the PEB interface card, 32k card and disk controller card.

[Sinphaltimus]

Here's the kit.

 

 

However; I lack the skills and possibly the tools to craft such tiny elements. I guess ilk have to find someone to assembly it for me. Or sell it and buy the preassembled kit.

 

Edited June 24, 2017 by Sinphaltimus

[Sinphaltimus]

So I got this built myself (Thanks for the solder paste suggestion Ksarul - It worked out great!) and it works!

 

[Sinphaltimus]

I was using the old Iron a lot recently. 

I was getting nervous about the temp sensors inside the clam shell of the controller, 32k memory, and the fire house interface reaching Temps of 101 f. Note, each sensor is mounted within 1/8" of one of the voltage regulators in each.

 

While I had it open to install the rs232 card I decided to add a fan in the middle of the peb blowing out of the back.

 

Far left is the firehouse then the RS232.

Far right is the disk controller then the 32k memory.

Fan is in the middle.

 

Saved me 17 degrees.

 

These are the Temps topping out.

 

 

[GDMike]

Nice, I'm a big fan