RC2014 Pro Instability.

[Adam Griffiths]

Hi All, I'm brand new to the group, please be gentle! I finished my build of the RC2014 Pro a few days ago, and it's been a little problematic. Odd, erratic behaviour. I am confident in my soldering and have done a visual check of it all. I've solder umpteen eurorack modules, successfully built an IMSAI 8080 High Nibble Replica (which is what sparked my interest in the RC2014 - I wanted a non emulating CP/M machine). I don't think its the soldering.

When I power it up, the 'Press Space Bar' message flickers a lot and won't respond, I need to keep pressing reset a lot until I get lucky and it's replaced with the start up options. I cannot get into Basic, when I press the letter for basic, it shows Warm or Cold start but is unresponsive to input. Then I'm resetting again as above. If I opt for CP/M then I can get in - and it's mostly stable at that point. Mostly.

If I try to use the download app (I've tried Zork1 and BBCBASIC) then it starts showing the ......etc until the same point (a different point for each of those programs) and will crash. Then I need to reset it again and the rigmarole described above starts again.

I used this tutorial https://z80.timholyoake.uk/how-to-transfer-software-to-a-rc2014-reliably/ to set up minicom. I had been using Screen prior, with the same issues.

I've no idea really where to start trouble shooting from this point onwards, and wondered if anyone else has suffered similar and resolved it. Or could recommend a starting point. I've read the trouble shooting docs on the main website. But they of course assume going in blind.

I'm powering from a block which should have more than enough amps. I'm connecting via minicom on a pi 500+ with the 5v jumper removed on the Dual Serial module.

Modules start with the CF mod in slot 4 then CPU, 64K Ram, Pageable Rom, Dual serial, dual clock ascending in that order.

64K Ram module jumpers are all set right.

Pageable ROM+ page size jumpers are low, low, high, high, high. Selection jumpers are none, none, none, low, low, high.

Dual Serial no jumper on port A 5v (using this port). Port B clock on, 5v on (not using this port).

Dual clock speeds are both jumpered 7.3728.

All modules are lined up in pin 1 properly.

I have the RP2040 vga module as well, but its off the board for now. It did work briefly when I first powered up the thing, but now it just shows the RC2014 logo if I do connect it, nothing else.

[timholyoake]

Hi Adam,

I've never had a problem other than file transfer, which is why I wrote the note you found. Sorry that I can't be more helpful.

Tim.

[Spencer Owen]

Hi Adam,

It sounds like your ROM jumpers are wrong.  For a 16k image (low, low, high, high, high) the Page Selection jumpers should only have jumpers on the very right 2 settings (A14 and A15). I think that removing the jumper from A13 should fix most of your problems.

There is also a conflict with the clock jumper. If you have a jumper on the Clock 2 header then you should not have a jumper on the Port B Clock pins on the serial module, or vice versa. In this situation where both clocks are running at 7.3728MHz it doesn't really matter, but if ever set Clock 1 and Clock 2 to different speeds then it will.

Although I haven't tried it, Tims downloading tutorial looks pretty thorough, and has the Tx character delay that I normally suggest.  See if things are better without the A13 jumper.

Let us know how you get on

Spencer

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[Michelle Lawson]

Well, this has got me to thinking..... Considering I'm intending on having my system run all the time; given it's intended role as a 'CP/M Server', do any of you just leave your systems up and running all the time? Be curious to see how stable everything is. I have done a bit of thinking, and if the clients are not making any requests, my system should just keep checking for a request forever. So if the hardware hold out, it could run for hundreds of years (LOL).

[Ed Silky]

Hi Michelle,

As you probably know, electronic circuits slowly degrade over time. It is most noticeable due to heat, so no electronic device is expected to last forever. You look like you have done very well in providing ample cooling, so hopefully you will get very long life from your system.

-Ed

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[sunnyboy010101]

I built my blue box system from Spencer's kits last summer. It has been on 24/7 since. I have a multi-port USB power hub on my UPS so things don't go down. Just this past week I built the Orton 3C into a blue box and it too is now on 24/7. I wrote a 'random blink' for the front panel I/O LEDS in C and run it all the time on the RC2014. On the Orton 3C I call the ROM IO-Left shift program to provide similar blinky LED fun.

-R

[Michelle Lawson]

Well, as soon as I get it all put together and functional to at least give me a command prompt, I plan on just writing 'something' to just exercise it a bit and just let it run. I'm not 100% sure what comes preloaded on the CF card, so maybe if it has MBASIC I'll write something with that,

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[Peter Onion]

I can't see a mention of what you are using for a power supply, and erratic behaviour could be caused by an inadequate power supply that is varying as the load changes.

PeterO

[Phil G]

Bear in mind that all "it was a dry-joint" conclusions start out by saying "I checked the soldering, there are no dry joints"...  :-)

[Adam Griffiths]

Very true, and I think there may be an issue with one of the sockets on the backplane. During my trouble shooting there was a moment where unplugging/replugging seemed to make the whole thing completely unresponsive, I'm not sure. So this weekend I'll just reflow for safety's sake. I have however, made some progress regardless. I'll pop that as an answer to Spencer's comments.

[Adam Griffiths]

I've made progress. With the jumper removed on the ROM board I seem to have stability. I have had the system booting without the 'press space' prompt skipping about, and left it on for an afternoon, occasionally using the dir command, changing directory (when will I learn to stop using cd A: (shakes head - knows better)) and using stat or dump.

Leaving both jumpers on the clock module and taking the jumper off the clock B pins on the serial module made CP/M unresponsive at it's command prompt. I could get into CP/M, but then make no further progress. So I currently have both pins on the clock and the clock pin on port b clock.

Remaining still is the issue of DOWNLOAD.COM freezing during operation. This leaves me wondering whether it could be one of three things. 

1) I don't know how to use the web based tool properly. Seems simple enough, though I don't know what the CPM User field is for, and am leaving it to zero. Fill last 128 bytes... always comes on, regardless of whether I select or deselect it. My browser of choice (Valkyrie) isn't supported. I do not have access to a windows machine to use the other tool.

2) The source files I am using are not trust worthy and are causing the problem. Can anyone recommend or link me a CP/M .COM file they know works, so I can remove that as a possibility please?

3) I need to further slow down the newline and character tx's in minicom (on my RPI 500+) - pretty much everything involved in this build is brand new to me. From it I hope  to learn about how the basics of a computer work, how to program some simpler assembly as a first step to other computer assembly languages AND join a community of which one day I hope to be a valuable member and less of a burden. 

Serial communications was not on the list, but as a 'Serial Learner' I am happy to add it to the list of things to learn. Though its right at the bottom of the list (hence why I bought the VGA terminal - I wanted a more plug and play option. This remains unplugged for now whilst I figure out the core modules).

Thanks Spencer for any further advice or thoughts (and anyone else too).

Adam.

PS: I cannot get into basic still, same issue, I can select it, but the system freezes and the cold/warm option. Though I am less fussed by this as I'd happier getting BBC Basic and MBasic running on CP/M.

[Adam Griffiths]

I'm not familiar with google groups, and I think I may have accidentally sent a private message to you? Or not at all? It's been a busy week. For completion...

This was my very first thought. I'm using the cable provided, 5v pin jumpers removed from the Serial module. And for a power supply a long board (4 gang socket thing) with 2 usb power supplies, rated at 3 amps each socket (not total). I measured it's output with a multimeter (not under load) and it was giving out 5.06v consistently. So I don't think it is that, and since I've had the system running stable now for an afternoon, and another evening. I'm coming to the conclusion the power supply is ok.

Thanks for your interest in helping. It's truly appreciated.

Adam.

[Adam Griffiths]

Hi Tim,

Your blog post/article got me up and running with Minicom, a brand new tool for me, so thank you for your indirect help in that area. I have replied to Spencer above, with a further question about using download etc. I would appreciate it if you had any insight there?

Adam.