464 + rediscovered - let it die or revitalise it?

[Deeko]

Here's the scenario:

Clearing out parents loft and find a box of 3.5" floppies from back in the day, a couple of which are uploaded in the forums/wiki already.

Further clearing brings a pleasant surprise, my old 464+ and CM12 (mono) monitor stuck in some bags. Age hasn't been kind, the tape deck door is completely detatched from the case, something on top of it for those years twisted and broke it  But filled with nostalgia for the old days I connected it up to see if it still lives, and it does...sort of.

Here's how it went


CPC 464+ found - YouTube

So it boots up to the F1/F2 screen but the keyboard is entirely unresponsive. Wait a while and Burning Rubber will start up and run through demo mode, keys still remain unresponsive. My first thought is keyboard membrane so I removed the case and gave it a thorough look over where nothing seemed out of place, broken etc.

Step 2, got myself a GX4000 paddle. The thinking being if it is the keyboard membrane I will be able to access F1 or F2 with that. Paddle arrived and booted up the plus but pressing the fire buttons did nothing so am totally in the dark of the cause. When pressing the directional buttons and fire buttons they all give a beep except for left on the d-pad so I'm unsure if the pad is working proper as I've no other 9-pin machine to test on.

So, it boots up and is unresponsive and I don't know if the keyboard isn't working, the paddle isn't working or if the cartridge itself might be corrupt in some way (I gave the edge connector a proper clean just in case).

Anyone with better experience and knowledge of such things than me (that's most people) experienced this 1st hand or heard of a solution to the same symptoms?

A bit of background on the machine, back in the day it was modified by the excellent Rob Scott (STS-fame) and has 128k memory, disc drive interface which I used a 3.5" A-Drive, ABBA switch for said drive. Things I'm hazy on are if I do or don't have Parados fitted. I did have a multiface 2 and Romboard back in the day, now gone,  and suspect Parados might have been in that as the cartridge doesn't look opened to replace the AMSDOS rom.

So is there hope it can live a full life again, or should I take it out back with a shotgun and put it to rest in pieces?

[arnoldemu]

don't let it die!

tradeinpost has plus keyboard membranes.

my 464 plus also has a bad keyboard

[Deeko]

Hi arnoldemu,

I wouldn't really let it die, I'd pass on to someone that would like to give it the TLC it needed.

I have looked at tradeinpost as a source for the membrane, but I'm not 100% sure if that's the problem yet. I got the GX4000 paddle to test because I thought even if the keyboard didn't work then the joystick port would and could still get to basic by fire 1. This hasn't happened so I need confirmation from someone more hardware savvy than me.

I will try and remove the case again later tonight and take a good high res picture to see if anyone here can see something obvious that I can't (hinting at Bryce in case he reads this  )

[MacDeath]

Feist - Let It Die - YouTube




Haha... nope don't let it die of course...
Those may be easy to repair or even mod into a 4128 with disk interface/plug.


Very often when the keyboard doesn't work, you actually just need to undust it, and unplug-replug it into the motherboard and it works again...

[Deeko]

Hi MacDeath,

It's already a 4128+ :-D Has extra 64k and disc drive interface (blue connector on the right in the youtube vid) from years ago.

Just need to work out what is / isnt working with it.

[arnoldemu]

I didn't know fire 1 got to basic. I thought it was only f1.

[beaker]

Definitely worth repairing or selling it to someone to repair.

[redbox]

It won't have ParaDOS in the cart because the f1/f2 menu is in the AMSDOS 0.7 ROM.

Good luck with the restoration...!

[Bryce]

I doubt it's the membrane, even with a dodgy membrane at least some keys would work. Have you checked that the membrane is still plugged in? If you're not up to restoring it, send it over and I'll fix it up (including the tape deck door).

Bryce.

[Deeko]

I didn't know fire 1 got to basic. I thought it was only f1.

That'll be me getting mixed up then, thinking more of fire 1 and fire 2 in Burning Rubber. It's odd though, when I leave it long enough for Burning Rubber to start the joypad doesn't do anything in either port. Is there a connection between joystick port input and keyboard that a broken keyboard membrane might account for?

It won't have ParaDOS in the cart because the f1/f2 menu is in the AMSDOS 0.7 ROM.

Good luck with the restoration...!

That'll confirm Parados was actually on the Romboard I had then

I doubt it's the membrane, even with a dodgy membrane at least some keys would work. Have you checked that the membrane is still plugged in? If you're not up to restoring it, send it over and I'll fix it up (including the tape deck door).

Bryce.

Hi Bryce,

I did get the casing off and the connections are pushed in pretty tight. I wouldn't want to feel like I was imposing if I sent it to you. PM me with details if you would still like to help restore it  Your 464+ Mod sticky is a proper good read, just wish I was as practicaly skilled as others are.



If it becomes functional again it looks like the next steps would be

   
• Get a bootleg cart with PARADOS on board. I've seen these on the 'bay from an Austrian seller.
• Compatible 3.5" floppy drive and loads of new disks to experience all those dsk images on the real deal
• Eventually a cable and power supply to connect to my old television as CM14's are so rare.

Thank to everybody that's given some insight to this. Always appreciated and it's why I love the CPCWiki and my fellow Amstraders


Derek

[MacDeath]

It's already a 4128+ :-D Has extra 64k and disc drive interface (blue connector on the right in the youtube vid) from years ago.

I was actually wondering... this extra connector is not supposed to be there on the 464... but was not really sure.


=have you tried to unplug-replug the keyboard ?
=checked for huge layer of dust between the keys and the membrane ?
=checked membrane for shortcircuits ? or scratches that would cut the circuit instead ?

[Deeko]

Checking that just now, she's naked and dirty as I post this (that means opened up and a bit grimey, not what some of you are thinking )

Looks really tidy, not that I'd know the difference of course.



And here's up close and personal

[MacDeath]

she's naked and dirty

Jizz In My Pants - YouTube



anyway a good point would be to have a cartridge with only Basic, no need to push f1 or f2... so you could test betterly.
also no need for a GX4000 paddle, any standard CPC compatible joystick from the era is enough.

if the joystick manages to work somehow in basic, then the "keys" functionnality should be OK, just need to check the whole circuit part from the keyboards. or perhaps not, are keyboard and controllers using the same circuit ?

http://www.cpcwiki.eu/imgs/e/e6/Edited_CPC_Plus_Vid_Mem_Schematic.gif
seems to be at the bottom of this one... is the AY controling the "keyboard X" ?
Haven't looked at such diagrams since long..

are the keyboard Y the KY1-KY10 on the ASIC ?
So keyboard is handled both by AY and ASIC ?


Does the AY works well ?
Perhaps a multiplexer somewhere ?



Service Manuals - CPCWiki
could be usefull.

[Bryce]

Your 464+ arrived yesterday. I'll give it a full inspection at the weekend and report back.

Bryce.

[Deeko]

Sweet! Thanks Bryce.

There's no rush though, have a good weekend.

Derek

[Bryce]

So I opened up the 464+, the good news is that is wasn't that major a problem. The pins of the two connectors for the membrane all had dry joints. A quick solder later and almost all keys were back working. A few were still giving problems but after a healthy blast of contact spray they came back to life too. So that's sorted.

Tomorrow I'll take a look at the tapedeck lid as I think that can be repaired too.

Your cartridge doesn't seem to have ParaDOS on it, it's never been opened.

Bryce.

[Deeko]

Excellent news Bryce.

I'll be more than over the moon if you get the tape lid repaired, it looked a sorry state when I last saw it.

About Parados, you're right it couldn't have been on the unopened cart so must've been on the long gone romboard.

Thanks again for fixing her up.

[Bryce]

So things went quite well today with the 464+. Unfortunately there was one slight setback. During testing I realised that the DEL key wasn't working and it turned out to be a crack in the membrane, I gave it a coat of silver paint but that didn't solve the issue, because the crack is on the bend just before the socket. You can still delete by using the back arrow and CLR, but a new membrane will be needed to fix the problem completely.

But anyway, the main job for today was the tapedeck lid. Unfortunately it had been broken in two places. The shaft on one side was snapped off and the hole for the other shaft had a piece broken off. The melted part of the hinge is due to the floppy port mod that had been done at some time in the past. Although the electronics were done fine, the guy did all the edits to the casing with a hot knife or soldering iron. Not pretty, but I cleaned it up a bit too.

[attach=3][attach=2]
[attach=4]

Luckily the part of the hole that was broken off was rattling around inside the CPC, so that could easily be glued back on.

[attach=5][attach=6]

The broken shaft was 3.1mm diameter and 3.5mm long, so the shaft of the button in the picture above will be used to replace it. The new shaft can't just be glued straight onto the surface, because the forces are too high and it would immediately break off again. So I needed to drill a hole so that the new shaft went through the plastic. This means drilling a 3mm hole through the plastic at exactly the right spot and at exactly 90°. This has to be planned well because you only get one go at it. Also, keep the drill speed low or the drill bit will melt a bigger hole.

[attach=7]

That's the hole done. The shaft on the button was actually 3.4mm diameter, so I had to sand it down slightly, then I added a dab of glue, pushed it through and removed the excess from the back.

[attach=8][attach=9][attach=11]

Make sure the glue is fully dried before you reassemble the lid in the CPC, otherwise you may end up gluing both sides of the hinge together. If all went well, you should have a working lid again.

[attach=11]

I cleaned and realigned the tape heads and gave it a go, all works fine again.

Bryce.

 

[paradroid90]

Looks like another CPC saved....Great Job Bryce :-)

[Deeko]

Looks like another CPC saved....Great Job Bryce :-)

That's Bryce,

Bringing 8-bits back from beyond one at a time 

Cheers Bryce, I would have glued myself to the casing by the 1st part, it's why I'm not allowed sharp or sticky things 

[Bryce]

More good news. After another coat of Silver paint the DEL key is back working, but I'm not sure for how long.

Bryce.

[Deeko]

She lives!!

Purely thanks to god of all things hardware    Bryce


She lives! - YouTube

Thanks again for the effort. I could sit opening and closing the tape lid all night.

The scart & power supply leads come from retrocomputershop. Just a 3.5" to arrive and I'll not be seen for weeks lol

[Token]

Nice reading, an other Amstrad saved, excellent work Bryce!
Congrat Deeko.


I never had to repair a keyboard membrane, but I just got a 664 and guess... I bought this: NEW Bare Conductive 10ml Electric Paint PEN Electrical Circuit PCB Repair Craft

[radu14m]

great work !

[Bryce]

Glad you're happy. I was really pleased with the tape lid result myself, it couldn't have turned out better. I'd still keep my eye out for a new membrane though. I've no idea how long my fix will hold.

Bryce.