Page 1 of 1

PCjr since the beginning

PostPosted: Sun Sep 08, 2019 4:12 pm
by TimsPCjr
Hi all,

Got a PCjr via a payroll deduction program IBM had in the 80's. Yes, paid the ransom for the Basic cartridge and DOS 2.1. Way later on I got 3 others from various school auctions for a few dollars each. It's also where I lucked up on the Rapport expansion kit, NIB! Sometimes the system has sat for a couple years without use but I'd always pull it back out to run the old programs. Currently it has a 720k and 360k drive but sent for the USB floppy emulator to try.

Re: PCjr since the beginning

PostPosted: Sun Sep 08, 2019 4:55 pm
by TimsPCjr
I just received akbkuku's power supply upgrade this week as voltage dropped in the original power pack. And today the USB floppy emulator to install. But at the same time and before installing either, the 35 yr old monitor may have kicked the bucket. It comes on but grey screen and buzzing. I'll recap first before trying any of the new monitor mods. Would be nice to keep it going. The screen was still bright and sharp before it failed.

Re: PCjr since the beginning

PostPosted: Mon Sep 09, 2019 4:18 am
by Chuckphd53
I have done a few Jr monitors, re-solder all the connections on the 'neck' connector and while you have it off, look around for cold/broken solder joints on the Caps/parts..
I have found these to be an issue as they are a hot spot for vibration...

Re: PCjr since the beginning

PostPosted: Mon Sep 09, 2019 3:21 pm
by TimsPCjr
Thanks, that gives me hope to know you've done this. I was going to get the values of all the electrolytic caps, replace and then reflow the solder all connectors as you said. I've been watching the TNT Amusements pinball videos on YT for quite a while now and that is their strategy on all the older machines they work on.

Re: PCjr since the beginning

PostPosted: Tue Sep 10, 2019 3:41 am
by Chuckphd53
I've seen a few also on YT.....interesting...
I picked up a monitor from ebay and when it arrived it had been dropped and the case was cracked, front and back...
Well.....not even trying it, (I knew better) I did a complete tear down, and cleaned the outer case with HomeDepot's Fabuloso, actually I found it worked really great to get the grease and marks off, actually make the outside case look new !

Now for the inside.... the main board was cracked and I had to use wire across the traces where needed. and Jumper wires if it was extensive..
the Yoke PCB had been jolted really bad...many of the larger components had cold solder joints and needed re-flowing....
As you mentioned, I did replace as many caps as I could find and after Cleaning the front control know with contact cleaner, re-assembly and now time to
press the power button....CLICK !
got a straight line across the screen....BUT it the High Voltage was working and also I could see the screen activity in the few this is a good thing..
Went back in and found as much as I inspected the Yoke PCB components, I missed two solder joints on the large Drive transistors...fixed those and put it back together..
Screen came on and with a little tweaking on the Yoke controls to center the Frame it was a Great Picture....
I now use this Monitor at home for my main screen and while I like using the Retro when playing it is hard on the eyes but I want the experience to feel real with my JR...

Bottom line is these monitors are pretty well made, and if you have the time/skill/$$ to invest in making it new again then it will pay off..
The key is go slow and even tho you look and see no obvious need to re-flow a solder are there so just carefully touch up as many as you can
and clean any flux afterwards.
It should give you many more years of operation for that Retro Look !

Good luck