I've got good news and bad news. The good news: I've managed to refurbish the power switch.
Turns out the mystery part I found rattling around in the case was one of the contacters. The circuit diagram shows that the power circuit uses only half of the switch, so I could reattach the missing contactor and still have a usable switch. The harder part was putting the switch back together. The catch which holds the upper housing to the lower housing was all but broken off. After several failed attempts trying to super glue the catch back into place, I settled with bonding the upper and lower halves directly. It seems to be holding together now, but I'm tempted to replace this switch in the future. The bad news is the computer is having power on issues. When I press the power switch the LCD displays a random assortment of lines, and pressing the power switch again does not turn the computer off. Pressing keys on the keyboard does not bring any noticeable response either. I've added some pictures of the LCD in my Drive. I suppose the cause could be anything from a capacitor failure to a short circuit, and I'm a little intimidated at the thought of examining the PCB for faults. Nevertheless, I've gotten this far and I'm not going to give up now. If anyone could provide troubleshooting advice I would really appreciate it. Thanks for all your help so far! Joshua. On Mon, Jun 12, 2017 at 4:47 PM, Josh Malone <[email protected]> wrote: > That's gotta be a pretty standard toggle switch, right? The service manual > gives a RS and a mfr part number, but neither of those numbers turn up > anything useful on the goog. Any chance there's markings visible on the > switch housing that might point to a manufacturer at least? > > On Mon, Jun 12, 2017 at 4:12 PM, Joshua Ray <[email protected]> wrote: > >> Well, I'm kinda stuck. >> >> The power switch is shot. I could repair the housing, but the contacter >> element is missing. At the moment it's just a plastic rod. >> >> I have found a small part rolling around in the housing, but I'm not sure >> if it's the missing contacter or not. I've added pictures to my Google >> Drive here: >> >> https://drive.google.com/drive/folders/0B-nu1y5KwPr4MDBXcjBZNXQ3T2M >> >> I tried shorting the pins on the power switch to check that the machine >> powers up, but I don't get consistent results each time I do. The machine >> appears to power on, but I haven't gotten a startup splash on the monitor, >> just vertical lines. >> >> I might be shorting the wrong pins on the switch, given my experience >> level. >> >> If the switch is irreparable, I'll have to get a new one from a scrap >> unit. I don't suppose anyone has a Tandy 200 power switch that I could buy? >> >> Any advice would be appreciated. >> >> On Thu, Jun 8, 2017 at 10:13 PM, Joshua Ray <[email protected]> >> wrote: >> >>> Success! Well, at least with getting the case apart. I took a pair of >>> credit cards and wedged them into one of the back corners, then followed up >>> with a long thin spoon handle for leverage. This way I didn't mar the case. >>> >>> My main issue now will be the power button. I've uploaded some pictures >>> to my Google Drive here: >>> >>> https://drive.google.com/open?id=0B-nu1y5KwPr4MDBXcjBZNXQ3T2M >>> >>> How do I go about reattaching this? Could there be trouble with the >>> damage on the click assembly? >>> >>> Thanks! >>> >>> Joshua. >>> >>> On Thu, Jun 8, 2017 at 12:30 PM, Bob Pigford <[email protected]> wrote: >>> >>>> Use a credit card? Why didn’t I think of that (as I slap myself on the >>>> forehead). Good one, Mike. >>>> >>>> >>>> >>>> Cheers! >>>> >>>> >>>> >>>> Bob >>>> >>>> >>>> >>>> *From:* M100 [mailto:[email protected]] *On Behalf Of *Mike >>>> Stein >>>> *Sent:* Thursday, June 08, 2017 10:45 AM >>>> *To:* [email protected] >>>> *Subject:* Re: [M100] Tandy 200 repair, guidance requested >>>> >>>> >>>> >>>> Hi Joshua, and welcome! >>>> >>>> >>>> >>>> I'm the guy who suggested you join up here and I hope you'll find the >>>> answers to your questions; I see Bob has already helped with advice about >>>> separating the case halves. >>>> >>>> >>>> >>>> My personal preference for prying apart cases held together with tabs >>>> that are not too tight is an old credit card; it doesn't scratch the >>>> plastic as a metal tool might. >>>> >>>> >>>> >>>> You can attach pictures to messages here but the total message size >>>> must stay below 64KB, so you might have to reduce their size and/or >>>> resolution. >>>> >>>> >>>> >>>> Good luck and, again, welcome! >>>> >>>> >>>> >>>> mike >>>> >>>> >>>> >>>> ----- Original Message ----- >>>> >>>> *From:* Joshua Ray <[email protected]> >>>> >>>> *To:* [email protected] >>>> >>>> *Sent:* Wednesday, June 07, 2017 4:48 PM >>>> >>>> *Subject:* [M100] Tandy 200 repair, guidance requested >>>> >>>> >>>> >>>> Hi all, >>>> >>>> >>>> >>>> I'm new to the mailing list. I was referred here from the vcfed forum. >>>> >>>> >>>> >>>> I have a Tandy 200 that needs some help. The power key is damaged and >>>> disconnected from the keyboard. I have a pdf of the service manual, and I'm >>>> trying to disassemble the device so I can check the internals and reattach >>>> the power button if it is serviceable. >>>> >>>> >>>> >>>> So far, I've removed the monitor and the four screws holding the bottom >>>> case, but I'm encountering a lot of resistance when I try to remove the top >>>> half of the case. Before I damage something, could anyone tell me if I've >>>> missed a step? >>>> >>>> >>>> >>>> Some forewarning: I'm a newcomer to vintage computing, and I only have >>>> basic electrical experience. I've got to start sometime though, and I'm >>>> willing to learn. >>>> >>>> >>>> >>>> Any help you can provide me will be appreciated! >>>> >>>> >>>> >>>> By the way, if you need me to attach pictures how do you guys usually >>>> handle images on this mailing list? >>>> >>>> >>>> >>>> Thanks! >>>> >>>> >>>> >>>> Joshua. >>>> >>>> >>> >> >
