Mike's PCjr Page

Just ordered one of these from you. Wish I had come across it before sourcing a power supply on eBay a few months back.

No problem. I hope many find it useful.

SOLVED!

The replacement capacitors took care of the low frequency hum. For anyone else experiencing odd issues with their IBM 4863 displays, it may be a good idea to replace all the electrolytic capacitors before you send it to the scrap yard.

I finally had some time this weekend to compile a list of capacitors needed for the PCjr Display. A fully completed recap will include both the analog board (power board, whatever you want to call it), and the neck board. The neck board has a protective shield in place that must be desoldered before...

The recap is 99% complete. I just overlooked a cap that’s hidden around the flyback transformer. Digging through my capacitor stash I found a cap with the correct uF rating, and one step up in voltage level. While it will work, it’s a cheapo cap that I purchased from RadioShack sometime ago. So, I’v...

Thanks for the tip. I had no intentions of swapping tantalum caps in place of the electrolytics. Replacement electrolytics are en route. I did specify that all replacements be rated for 105C instead of 85C.

So... As I was removing a few caps from the board, it didn't take long to find signs of leakage. If you look closely at the image, you can see a darker area in the middle of where the capacitor sits. That is cap goo. For reference, the location on the board is labeled C953. The capacitor value is 33...

I’ll compile a list of replacement capacitors and post it here. There are quite a few!

I went ahead and disassembled the monitor to the point that I was able to remove the analog board. I'll be recapping both the analog board and neck board. I'm no electronics guru, but I speculate that there are capacitors responsible for filtering low frequency noise that could works its way into th...

Hi guys. I just cleaned up my new-to-me PCjr monitor tonight, and connected it to the PCjr to test operation after replacing all the motherboard and power supply capacitors. Unfortunately, when I power on the monitor, the speaker emits a low frequency hum. The pitch changes when the computer is powe...