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General Category => Technical support - Hardware related => Topic started by: Loupingre on 23:17, 13 June 21

Title: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 23:17, 13 June 21
Hi everyone :)

I've bought some days ago a CPC 6128+ on ebay with technicals issues : keyboard problem and floppy drive not working.
As I've already repair my 6128 floppy drive (changing the belt), I was confident to be able to fix these 2 issues (as I've also read the NR02 solution for the 6128+ keyboard).
At the first start, I saw indeed the keyboard problem : keys y u i o h j k l n , ; and SPACE were not working (all the others were ok, and key combinations works, like soft reset). And the floppy drive was not working at all : no led light).

So, the first thing to do was to clean the dust inside the CPC (there was a lot), and see if there were any chemical leaks from capacitors.After that, I've removed the old belt (it was awful) from the floppy drive, cleaned everything and replace the belt.I also removed the NR02 resistors and try a new test : no luck, no led light and still the keyboard problem.

I 've decided to clean the membrane connectors (with isopropyl alcool), clean the connectors (with a thick piece of paper), but still problem occur with the keys. So It was time to open the keyboard and take a look inside. And I've quickly found the problem : there is a hole between the "]" and the "è" keys :(

(https://i.ibb.co/Mk3jTm9/Hole.jpg) (https://ibb.co/Mk3jTm9)

And from the membrane side (sorry for the tablecloth colors ^^) :

(https://i.ibb.co/7jXjG1R/Membranes.jpg) (https://ibb.co/7jXjG1R)

2 conductive tracks are badly damaged :( I've tried to fix them with 2 small tin strands but it's not working.I'm not realy sure if it's fixable, but if you have some advices, I'll take them ;)

I've also searched on Internet to see if new CPC 6128+ membranes can be found, but I've found nothing :(
Oh, I haven't found either the problem with the floppy drive : the 5V is present on the floppy connector but I didn't look for more.


Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 00:39, 14 June 21
Silver conductive paint can be used to repair broken tracks on the membrane

This guy shows it on a normal PC keyboard, but it's probably the same on the CPC:
https://youtu.be/tJXRhR-7YNM?t=197
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 08:50, 14 June 21
Thxs for your answer :)
I'm not sure if this solution can be used : the hole goes through the membranes :( I don't know if sticky conductive tracks exist but it can be the right thing to do.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 09:24, 14 June 21
Quote from: Loupingre on 08:50, 14 June 21
Thxs for your answer :)
I'm not sure if this solution can be used : the hole goes through the membranes :( I don't know if sticky conductive tracks exist but it can be the right thing to do.


On a German forum someone recommended to repair the cracked  part at the connector of the membrane with a piece of Tape and then use the silver to replicate the tracks on this piece of tape. Not sure if that could be an option here.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 19:13, 14 June 21
I've tried to remake the 2 missing tracks by adding some very thin metal wires.

Here ares the membranes holes :

(https://i.ibb.co/8X2nVS6/Membranes-holes.jpg) (https://ibb.co/8X2nVS6)

And my test repair :

(https://i.ibb.co/zrHVWVS/Repair-test.jpg) (https://ibb.co/zrHVWVS)

It's slightly better - I've got some letters back - but not all of them => è ! y u h j n SPACE are still missing :(
I'm not sure if it's totally fixable and reliable ... Do you know if it's possible to buy membranes somewhere ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: TotO on 20:02, 14 June 21
May be you can try to fix it with a conductive ink pen.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 20:06, 14 June 21
Quote from: TotO on 20:02, 14 June 21
May be you can try to fix it with a conductive ink pen.
His problem is that there's a hole in the membrane, so the ink needs to go all the way around a rough surfaced hole (keep the jokes to yourself on this one). It's going to be extremely difficult to get a reliable, long-term fix for this, without replacing the membrane.

Bryce.

Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: TotO on 20:13, 14 June 21
Yes. I think he can try to draw "around the hole" using something like that:

(https://s1.qwant.com/thumbr/0x380/8/7/39eda6ebbd3dca0184b9ba95b11f875ba06c1d4df73a21c32cb0e6d09c1e79/Black-Technology-UK-imported-conductive-ink-pen-liquid-circuit-kit-10ml-winder.jpg?u=https%3A%2F%2Fae01.alicdn.com%2Fkf%2FHTB1zpGKRVXXXXXjXXXXq6xXFXXXT%2FBlack-Technology-UK-imported-conductive-ink-pen-liquid-circuit-kit-10ml-winder.jpg&q=0&b=1&p=0&a=0)
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 20:14, 14 June 21
Quote from: TotO on 20:13, 14 June 21
Yes. I think he can try to draw "around the hole" using something like that:

(https://s1.qwant.com/thumbr/0x380/8/7/39eda6ebbd3dca0184b9ba95b11f875ba06c1d4df73a21c32cb0e6d09c1e79/Black-Technology-UK-imported-conductive-ink-pen-liquid-circuit-kit-10ml-winder.jpg?u=https%3A%2F%2Fae01.alicdn.com%2Fkf%2FHTB1zpGKRVXXXXXjXXXXq6xXFXXXT%2FBlack-Technology-UK-imported-conductive-ink-pen-liquid-circuit-kit-10ml-winder.jpg&q=0&b=1&p=0&a=0)

Never tried that stuff, but I've always been curious as to how good it actually is.

Bryce.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 20:40, 14 June 21
Thxs for your answers TotO & Bryce !

Maybe I 've found another possible fix : a copper foil tape which is dual conductive adhesive. If I manage to cut very thin lines, maybe these lines can do the trick.
And if it doesnt work, I'll try the electric paint pen.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 21:42, 14 June 21
Quote from: Loupingre on 23:17, 13 June 21I've also searched on Internet to see if new CPC 6128+ membranes can be found,

Try this guy here: https://www.facebook.com/groups/5357712057/permalink/10158458727612058

I am not sure if any are left but I also didn't see that he said they were sold. I got a brand new keyboard from him and everything was fine.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 22:32, 14 June 21
Quote from: eto on 21:42, 14 June 21
Try this guy here: https://www.facebook.com/groups/5357712057/permalink/10158458727612058 (https://www.facebook.com/groups/5357712057/permalink/10158458727612058)

I am not sure if any are left but I also didn't see that he said they were sold. I got a brand new keyboard from him and everything was fine.

Well ... hum ... In fact I don't have a facebook account (yes I know :D ).Can you kindly ask him if there were any plus membranes left ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 23:30, 14 June 21
Quote from: Loupingre on 22:32, 14 June 21Can you kindly ask him if there were any plus membranes left ?

Done! I will let you know if he answers.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 08:58, 15 June 21
Quote from: eto on 23:30, 14 June 21
Done! I will let you know if he answers.

Great !!! On my side, I've bought the copper tape, as the electric paint has some resistor value (55Ω/sq).So I can paste some thin copper lines around the hole.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 09:52, 15 June 21
55 ohms per square is rather high. It might work though.

Bryce.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 11:14, 15 June 21
Quote from: Loupingre on 22:32, 14 June 21Can you kindly ask him if there were any plus membranes left ?

Check your personal messages. He still has some membranes. I sent you his email address.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 12:13, 15 June 21
Quote from: Bryce on 09:52, 15 June 21
55 ohms per square is rather high. It might work though.

Bryce.

I'll try to fix the membranes with the copper tape, but if it's not working, I'll try the electric paint :)

Quote from: eto on 11:14, 15 June 21Check your personal messages. He still has some membranes. I sent you his email address.

Great !!! Thxs !!!
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: m_dr_m on 16:10, 15 June 21
Even after that, you'll still have a problem: that's an Amstrad Plus.
Easy fix: Find a CPC 6128!
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 22:00, 15 June 21
Quote from: m_dr_m on 16:10, 15 June 21
Even after that, you'll still have a problem: that's an Amstrad Plus.
Easy fix: Find a CPC 6128!

Héhé :) Maybe that's true : my 6128 from 1987 is still working well !
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: eto on 22:10, 15 June 21
Quote from: m_dr_m on 16:10, 15 June 21that's an Amstrad Plus.

what problems do they have? I have a Plus and haven't had an issue yet.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 08:25, 16 June 21
Quote from: eto on 11:14, 15 June 21
Check your personal messages. He still has some membranes. I sent you his email address.

In fact he has many membranes left !!! I'll just buy one, as I'm not the only one seeking for membranes :)
Thxs again eto !
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 11:31, 19 June 21
Some news about my 6128 plus :

* I've tried yesterday to use the copper tape I've bought but it's not working :/ For now I just tried to continue the damaged tracks, not paste around the holes (next test ^^).
* I've also tried to fix the floppy drive (no led light at all) :

- When I type "cat", there is no noise and no led light (retry do nothing too).
- I've measured the connector voltage, there is 5V.
- I've remade some soldering (to avoid dry soldering) but no luck.

Have you ever had this floppy drive problem ? What can I do next ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: tjohnson on 11:40, 19 June 21
I've successfully used electrolube silver conductive paint to repair a membrane on cpc and other things like my old school calculator.  Maybe repair the hole with tape then paint the conductive paint between the original tracks.  Repaint all the contacts on both socket connector tabs on the membrane, that worked a charm for me.


https://www.ebay.co.uk/itm/ESCP03B-Electrolube-silver-conductive-paint-3g-/193711908690?_trksid=p2349624.m46890.l49286
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 14:05, 26 June 21
Keyboard fixed ! The new membrane has done the trick :)

Next step, fix the floppy drive. As I said before :

* No sound at all (no spin noise, no access noise) with cat command (and retry). And no led light.
* 5 V is present on the floppy voltage connector.* As far as I know, there are no dry soldering.


Have you a "check-up list" for a (too) quiet floppy drive ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 15:58, 26 June 21
Quote from: Loupingre on 14:05, 26 June 21
As far as I know, there are no dry soldering.

What does that mean? You looked and found none? Or you're assuming? Have you checked the joints on the power connector and then checked whether the motor turns at all (they can be very quiet without a belt).

Bryce.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 17:27, 26 June 21
Quote from: Bryce on 15:58, 26 June 21
What does that mean? You looked and found none? Or you're assuming? Have you checked the joints on the power connector and then checked whether the motor turns at all (they can be very quiet without a belt).

Bryce.
Hi Bryce,

Yes, I've already looked and done some re-soldering on J2. When the CPC is switch on, I 've measured 5V on J2. It seems to me that the motor never turns on.


(https://i.ibb.co/FDf2WXQ/Drive.jpg) (https://ibb.co/FDf2WXQ)



Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: gerald on 17:45, 26 June 21
It might be Q3 that is blown (just behind J2). You should see 5V on each side of its 2 pins. If not, just short it  ;D .
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 18:25, 26 June 21
Quote from: gerald on 17:45, 26 June 21
It might be Q3 that is blown (just behind J2). You should see 5V on each side of its 2 pins. If not, just short it  ;D .

I've got 3,35 V on Q3, is it bad or not ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 10:25, 05 July 21
Any other advice ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 10:35, 05 July 21
Quote from: Loupingre on 18:25, 26 June 21
I've got 3,35 V on Q3, is it bad or not ?

On which side of Q3 do you have 3.35V? Input or output? Either way, both would be bad, it should be 5V.

Bryce.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 22:38, 05 July 21
Hi Bryce,

* On J2, I've got 5V between pin 4 and pin 3/2.
* On Q3, I've got 3,3V today between the 5V track (red probe) and the other (black probe), and -3,3V between the other track (red probe) and the 5V track (black probe).

[Edit] Quick update ! I've "shorted" Q3 (with a small wire) to do a test and the drive is working (I've successfully launched Robocop ^^)! Is Q3 a fuse or something like that ?
I 'll prefer to replace the component instead of leaving the wire (if I can find something which can replace Q3).
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 11:59, 26 July 21
Hi all,

Back from holidays :) Any advices about the Q3 component ?
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Bryce on 12:46, 26 July 21
We never quite worked out what Q3 is, but it's assumed that it's some sort of fuse. I just short it out as you did when I find one that has failed.

Bryce.
Title: Re: 6128 plus problems (keyboard and floppy drive)
Post by: Loupingre on 16:03, 26 July 21
Thxs Bryce ! So my 6128+ is fixed, I'll just need to add an external hxc/gotek :)
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