6128 PSU

[Gryzor]

Hello guys!


Picking up a lovely 1084S next week; this is going to replace my trusty CTM*. The reason is, I can use the 1084 with more stuff and thus cut down on the circus that is currently going on in my spare room.


Anyhow, Bryce was kind enough to provide the pinout for the sub-D connector, and I guess I can make that cable myself (hm. Maybe I should also buy Bryce's 5V adaptor ). Just wanted to ask if anyone knows of anyone who sells reliable, small PSUs for the CPC? I don't want to mess with PC PSUs - trying to cut the mess down, remember


Thanks!
T


PS ooh I'm gonna have lovely sound, too, without the need of extra (though better) speakers




*(hm, must install footnotes on the forum again) it's sad because my CPC setup includes the TV tuner and radio/clock under the CTM, and I'm going to miss that... perhaps I'm going to spray-paint the 1084 with vinyl paint, since it's easy to remove, but onlly if it's easy enough to disassemble.

[Bryce]

If you have a Spectrum +2/3 PSU (which I think you do) you can make a small adapter to power the CPC with that (even without my 5VCPC).

Bryce.

[Gryzor]

Nope, I think I gave mine to you a while back


But yeah, that'd be a nice solution!

[Bryce]

I thought you still had another Spectrum?

Bryce.

[Gryzor]

I think not (at least a +2)? But I may be mistaken. Gotta catalogue that mess some day...

[1024MAK]

Only a +2A PSU with a DIN plug, not the 9V (nominal) type that comes with a Grey +2 mind!

Mark

[||C|-|E||]

I am using a chinese linear PSU that is actually very nice and does not cause any kind of interference with the CRTS  . I had to ground it myself, but it is a really easy modification. I can look for the link if you don't find the other 

[Gryzor]

@1024MAK good advice, I didn't remember the distinction but also for anyone else who might stumble onto this thread...


@||C|-|E|| here's an interesting question - how important is grounding with the CPC? I know @Bryce will want to have my head even for asking, but I seem to remember that, in Greece at least, the monitors were sold with groundless plugs (the common 2-pin European plug), not the schuko one. But maybe I'm mistaken...

[keropi]

^ the 1084s use a pc-style power cable so they have ground allright.
You only need 5 wires for the video cable: R-G-B-Luma-GND and you'll get an awesome picture 

[Bryce]

My 1084 has a 2 pin plug, so no ground.

@keropi: R, G, B, Sync and ground are the correct signals to use.

Bryce.

[||C|-|E||]

Strictily talking, you don't need to ground it. For example, my DD-1 has no ground  . I prefer, however, to ground the things if this is possible and have a common ground for the machines that are part of the same setup.

[Bryce]

No FD-1 had a ground connection, not even the UK versions. Unless the device had exposed metal on the outside, there was no requirement to have a ground.

Bryce.

[||C|-|E||]

Yup, I wanted to say FD-1,  I always write it wrong  . The linear PSU I was talking about, however, has a nice metallic case. It is good to ground it, if possible 

[keropi]

My 1084 has a 2 pin plug, so no ground.

@keropi: R, G, B, Sync and ground are the correct signals to use.

Bryce.

does the "plain" CPC 6128 output sync? I thought it was LUMA


edit:
I see now it outputs both    - sync it is then... as a sidenote LUMA works too on the 1084 , at least the 1084S-P1 (and 8833-II) variant ... they also have 3 pins in the power input - one is ground


also, the video output in general, is it a TTL level one? or it's just SYNC that is TTL?

[Bryce]

Luma will work on most monitors as it also contains the Sync signal, however some monitors will not sync properly with Luma unless the extra data has been filtered out.

Only the Sync is TTL, all other signals are analogue.

Bryce.

[keropi]

so isn't it better to connect LUMA instead and not SYNC on a monitor? it's quite a voltage difference afaik

[Bryce]

The sync pulse in the Luma signal is exactly the same voltage level. TTL levels for a sync signal are fine on any monitor.

Bryce.

[keropi]

The sync pulse in the Luma signal is exactly the same voltage level. TTL levels for a sync signal are fine on any monitor.

Bryce.

This I did not know , I thought LUMA was analog too. 

[Gryzor]

I don't mind the luma vs sync discussion, any ideas about a PSU then?


@||C|-|E|| , can you clue me in?

[||C|-|E||]

Sure, I just need to check in my computer! I am still in Spain, with the phone only 

[1024MAK]

There are two reasons for connecting to earth / ground (where this is a connection to a metal stake or buried grid in the ground or equivalent, either local to your building or at an electrical sub-station / power line pole).

• For electrical safety - any exposed metal work must be earthed/grounded where there is a possibility of a failure of a wire / connection point / or of insulation resulting in the case becoming live at mains voltage, or any other dangerous voltage.
• For suppresson of electrical noise - screening and radio frequency interference (RFI) suppression works better if the system has a connection to earth/ground.

If you are buying a new 5V power supply, I suggest you buy a known branded item, from a reputable electrical supplier, the things to look for are (or to ask for):

• Is the mains voltage correct for where you wish to use it?
• Is it a fully regulated type?
• Is the output regulated to +5V within +/- 3% (or better)?
• Is the unit rated for a continuous output of 2A (not powering a disk drive), 3A (powering a disk drive) ?
• Does it have short circuit output protection, overcurrent protection, overvoltage protection?
• Does the separation and isolation between the low voltage output and the mains voltage input comply with the electrical standards of your country?
• Is it made to the double insulated standard, or if not, is all exposed metalwork correctly earthed/grounded (with a suitable three pole mains plug)?
• If it is a switching type (SMPSU - switch mode power supply unit), does it have proper RFI filtering

Mark

[1024MAK]

Here are some links

There are a number of big electrical/electronic distribution companies, two are:
http://www.farnell.com
http://www.rs-components.com/index.html

Of these two, RS has these 5V types available:-
"Plug-in"
"desktop"
I have not fully checked the specifications on all these. But it gives you some idea of what you are looking for.

Now, if you want a PSU that outputs a 12V output to supply a floppy disk drive that needs both 5V and 12V, then none of the above will be suitable. As you then need a dual output type. The 5V output still needs to be fully regulated, but the 12V does not have to be fully regulated.

Mark

[Bryce]

I don't mind the luma vs sync discussion, any ideas about a PSU then?


@||C|-|E|| , can you clue me in?

Sorry for going off topic Gryzor, just to end the Luma discussion: Luma is an analogue signal with a TTL sync pulse superimposed on top of it.

Bryce.

[Gryzor]

No worries Bryce, it's interesting indeed!


@1024MAK , thanks for the links. Indeed I do need a combo PSU, hence why I'm asking here - if it was just a matter of a good PSU for the main unit it wouldn't be so hard to get one... On the other hand I do think I have an external PSU for my HxC so it's not fatal if the drive stays unpowered.

[||C|-|E||]

Sooo... back in UK again!

This is the PSU I bought:

http://www.ebay.co.uk/itm/Hifi-linear-DC-5V-output-power-25W-USB-amp-DAC-external-power-supply-/131524729527?hash=item1e9f7c1ab7

I opened it to ground and check it and the quality of my unit is actually very good. Moreover, these are very easy to repair and do not interfere with CRT monitors. This one is 5V only, though...