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464 plus with scart cable

Started by Anthony Flack, 00:17, 22 February 23

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Anthony Flack

So, I have recently acquired a CPC464 Plus from the UK. No monitor, but it came with a (modern) power supply and scart cable from a retro computer supplier. 

Unfortunately, I don't have anything here with a scart input to plug it into.

I do however have an original Amstrad CTM 640 monitor, and an Amiga 1084S monitor. I figure it should be relatively simple to make an adaptor for one of these, ideally the Amiga monitor as it has speakers, and that way the two CPCs can sit side-by-side. The Amiga monitor is a better match for the wannabe-Amiga stylings of the Plus, anyway.

Is there any traps I need to look out for? Maybe the sync line?

What would be better yet is if there is some cable I can order, either to plug into the scart cable or to replace it. I don't mind having to solder up a cable but I'll take the lazy option if it's there.

Thoughts? 

eto

I doubt you can find an adapter but it seems to be straight forward to make one.

Check out this thread: https://www.cpcwiki.eu/forum/hardware-related/amstrad-cpc6128-gt-commodore-1084p/

You can go the half lazy route and buy a 9pin serial cable (as long as all pins are connected), cut off one side and solder on the Plus monitor plug. It's probably good enough for the signal.

Anthony Flack

I think that is exactly what I will do, as I do have a spare male-to-female 9 pin cable lying around somewhere and unexpectedly, I have a spare plug for the Plus end as well (it's the same plug as the MSX maybe?), and I'm getting eager to see if my new Plus actually works.

I thought there might be some kind of adaptor to plug the scart cable into the 1084 but no worries, I'll bust out the soldering iron. 

Anthony Flack

#3
It looks like 00WReX has done exactly what I aim to do... Amstrad Plus into a 1084S-P1. Nice.

QuoteAnd for the Commodore 1084S-P1 that has the 9-Pin RGB connector.

AMSTRAD    ==>  1084 9-Pin

1 - RED      ==>  3 - RED
2 - GREEN  ==>  4 - GREEN
3 - BLUE    ==>  5 - BLUE
4 - SYNC    ==>  7 - CSYNC
5 - GND      ==>  2 - GND

Anthony Flack

Boom, job done. And don't they look nice together!


The tape deck isn't closing properly, which turns out to be because one of the tabs is broken off.



A little screw fixed that, although it still seems to struggle to latch.



Now I see that the keyboard has issues, though. I'm going to give the membrane and sockets a thorough clean, and if that fails I suppose a new ($$$) membrane will be required.


Anthony Flack

Since I have never actually used a Plus machine before, here are some first impressions:

I still think the original 6128 looks nicer. 

The removal of the cassette counter is pretty unforgivable, and combined with no tape loading sound, makes using the tape deck unnecessarily difficult if you're dealing with a multiload tape.

Burnin' Rubber was a really poor choice of pack-in game. Sure the colours are nice, but I mean, if you want to make your system look slow and underpowered in the 16 bit era, a software-rendered 3d game will do it. If you want people to think the sound quality is bad, that awful droning engine sound will do it. If you want people to start looking for something else to play after ten minutes, yep, that will do it.

Too bad they didn't pack in something like a compilation of four small and fairly simple arcade-style games that ran at 50hz and showed off the sprites and scrolling better. They might have sold more GX4000s if the pack-in cart had more entertainment value.

d_kef

You might already know that, but if the keyboard is still erratic after the membrane cleaning take a look here before ordering a new one.

d_kef

Anthony Flack

I did see that; it makes me a little nervous though. Why'd they include the resistor network in the first place?

My membrane seems to have an issue with stuck keys rather than unresponsive ones. And a few of the keys register as the wrong key it seems, so something goofy going on with the matrix I guess, maybe it's shorted somewhere.

Dang those new membranes are expensive though. 30 euros for the membrane and 37 euros to post it?!

d_kef

Well the article gives an explanation, but even if the AY in your 464+ is the one without internal pull-ups it turns out that the resistance of the membrane itself could have changed over the years.
Another reason for stack keys or keys giving wrong output could be a defective AY. You can check by pulling out the membrane and shorting the corresponding contacts in the connecting sockets.

d_kef 

eto

Quote from: Anthony Flack on 08:46, 27 February 23I did see that; it makes me a little nervous though. Why'd they include the resistor network in the first place?
My explanation: The Plus was not designed by the same people as the CPC. There seem to be a couple of bugs in the design. 

Just recently my Plus started to show the same problem. As I already cleaned the membrane, I removed the resistor array and all is good again. 

Where did you find the membranes? I only know that Sintech has made new membranes lately and their shipping is even more expensive. 


Maniac

Quote from: Anthony Flack on 08:46, 27 February 23I did see that; it makes me a little nervous though. Why'd they include the resistor network in the first place?

My membrane seems to have an issue with stuck keys rather than unresponsive ones. And a few of the keys register as the wrong key it seems, so something goofy going on with the matrix I guess, maybe it's shorted somewhere.

Dang those new membranes are expensive though. 30 euros for the membrane and 37 euros to post it?!
I hesitated for a few years before removing the resistor network. Finally did it in the last few months and the keyboard is reliable again.

Anthony Flack

Looking at my keyboard membrane, it seems the spacing material is a little eaten away in some places, which may explain the behaviour. The right cursor key is almost always stuck on, and when I press W the 1 and 2 keys trigger as well. Perhaps I could try sticking a little piece of card in those spots or something like that.

The tape door absolutely refuses to latch, which is odd. It seems like the latch doesn't quite reach the part of the door it's supposed to latch onto. Maybe I'll just release the spring and be done with it. Better than having it pop open all the time. The tape deck works though; there was a tape inside it when I got it... part of a compilation which is now missing one cassette. Karnov on one side and Super Hang On on the other. Not exactly the greatest games in the CPC library, but they do load.

Anthony Flack

Quote from: d_kef on 09:10, 27 February 23You can check by pulling out the membrane and shorting the corresponding contacts in the connecting sockets.
I'll give this a try as well to be sure.

Anthony Flack

Quote from: d_kef on 09:10, 27 February 23the article gives an explanation
I've translated the article and read it now, and feel better about removing the resistor network. But I don't think that's actually the problem here; I do suspect its physical degradation of the membrane spacing and I'm going to have a crack at fixing that right cursor button and see if I'm right. If that's a disaster, it will be off to Syntec for me I suppose. If it simply makes no difference, I guess I'll yank the resistors, but this doesn't seem like an under-voltage issue to me. 

I haven't tried shorting the contacts yet, although the stuck key went away when the membrane was unplugged, so I'm betting it would be fine.

The CPC also came with an M4 board, which I know next-to nothing about, so after I get the keyboard working I'll be wanting to figure that out as I intend to do more with this machine than just play Burnin' Rubber, Super Hang On and Karnov.

d_kef

You'll appreciate the cartridge emulation of the M4, and not only...

d_kef 

Anthony Flack

#15
So I was fiddling around with the membrane a bit more, and while I had the case open, I was looking at that resistor network sitting there and thought "what the hell" and wiggled it until it snapped off.

I also opened up the corner of the membrane and patched up the part of the spacing material that had deteriorated around the right arrow key, using some little pieces of electrical tape to build up the height.

The right arrow key seems to be working fine now, but the keys in some other areas are worse if anything. Pushing certain keys triggers multiple keys. Pressing on the case triggers some keys. I think the deteriorating spacing material is to blame, but rather than try to put tiny patches of electrical tape everywhere I should probably bite the bullet and buy a new membrane.

I also disengaged the tape deck door spring and now the door DOES latch, but only just. It also doesn't pop up anymore, which isn't a huge deal, as I don't actually own any CPC tapes any more except for that Karnov/Super Hang On one. The latch only latches by a hair though, maybe the case is slightly warped, maybe somebody replaced the drive belt and put the cassette unit back slightly wrong, because the latch is on the cassette unit and the door is on the case. The tape goes SKROINK.... SCROINK... SCROINK... when it plays but seems to load fine.

Anyway I'm not too bothered by that. I will order a new membrane. 

Anthony Flack

If I feel bad about the cost of the postage I will simply compare it to the price of vegetables right now. $7 for a cabbage?! Ok, I can buy the membrane now.

And it is done.

Anthony Flack

The new membrane arrived today and everything works perfectly now. Full credit to the good folks at Sintech whose hard work let me solve the problem by simply spending some money. Now everything feels great, the CPC is fully responsive and I guess tomorrow I will try to figure out how to use the M4 board. 

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