78 replies to this topic

[tupinamba]

Related to Step 22: Building a linear PSU

Update:

The new PSU had - depending on week day and weather :-) - some small noise issues... it was never really bad... but perceptible... like a 50hz hum and some infrequent "crackles"... I really wanted to solve the problem and was wondering why the new PSU wasn´t better in terms of noise than the old PSU... it has quality components all over... so... back to the assembly table :-)

Hey,
I'm thinking of building my own PSU using the RetroDonald schematic. Could you be more precise about the improvements you made to it ?
Thanks !

[Hawkeye]

The improvements consisted of
a) a second 2.200 uF capacitator for improved ripple softening after the rectifier.
b) closer installation of the voltage regulator filtering capacitators - you can solder them directly on the voltage regulator pins (this really helped a lot in noise reduction, before, it sometimes picked up stray "switcher" noise from nearby PSUs).

Of course, you could do even more things with the PSU, but I doubt that you will hear much difference... Orange_hand is working on a PCB, you could contact him.

Greets and have fun!
Peter

Edited by Hawkeye, 08 October 2011 - 11:57.

[Gilesjuk]

Just finishing off my MB-6582, some tips I think are useful.

When soldering the PCB interconnect leads to the pin headers put some heatshrink tubing over the cable before soldering. After soldering all the connections you can slide the tubing over the joints and shrink the tubing over the soldered joints. This reduces the possibility of wires shorting or coming off. It also looks more professional.

Also, I'm soldering the wires to the pin headers before fitting them to the PCB. It is a lot easier to solder the wires to the pins when they are flat on the bench, although you will need to place something on the pin header to stop it moving around.

[ilmenator]

Also, I'm soldering the wires to the pin headers before fitting them to the PCB. It is a lot easier to solder the wires to the pins when they are flat on the bench, although you will need to place something on the pin header to stop it moving around.

Have you soldered the headers to the PCB already? You should notice that the wires easily come off again in the process, because of the heat you apply to the header/PCB joint.

[Gilesjuk]

Have you soldered the headers to the PCB already? You should notice that the wires easily come off again in the process, because of the heat you apply to the header/PCB joint.

They won't with the heatshrink sleeving holding them in place (in theory).

A crocodile clip might also help, in both keeping the wire in place and dissipating the heat.

[ilmenator]

If you have the heatshrink in place, the croco clip will destroy it when heating up. Either way, you don't want the heat you put into the solder joint to dissipate! You heat it up for a purpose, by adding the croco clip as heat spreader you increase the risk of ending up with a cold solder joint.

[Gilesjuk]

I will try it later. But either way I think it is better to insulate between pins.

Edited by Gilesjuk, 17 February 2012 - 15:32.

[ilmenator]

I will try it later. But either way I think it is better to insulate between pins.

Yes, I totally agree with that!

[Gilesjuk]

Well, it works. The wires haven't come off but then i use a temperature controlled iron. But I'm having trouble keeping the connectors onto the right angled pins, so I may just end up soldering wires direct like wilbas original.

This is the only bit I don't like about MB6582, but then I guess the CS is using simple technology instead of complex serial buses (which would mean less wires).

[orange_hand]

Hi,

my recommendation is to use the following, easy and clean:

http://www.reichelt....0e328e8b2424f6b

Here are the results:



I hope that helps.

Cheers
orange

[Blatboy]

First of all, thanks so much to Hawkeye for putting this together. My mind is completely blown. I will build this. I'm a bit of a noob, but not completely inexperienced, and have already done some less involved projects/kits.

I'm unsure if I'll end up using the PT-10, as I'm thinking about using an old c64 case for an enclosure. I saw a picture of one here somewhere and I like the idea of keeping a non working 64 from a landfill, plus I'm hoping to get one with a working power supply. We'll see though... The PT-10 setup is pretty damn sexy...

I'm assuming that if I did use an old c64 case, that I could still use the basics of this tutorial, yes? Obviously anything involving the case would change, and I'd probably have to do some tooling on the back of the C64 case for the back panel. I'm on the fence here..

Anyway, thanks again Hawkeye.

[Gilesjuk]

Hi,

my recommendation is to use the following, easy and clean:

http://www.reichelt....0e328e8b2424f6b

Too late, they would have been great. In the end I soldered normal IDC to the main board and used right angle pin headers on the control surface.

If the cable is too thick the resistance to bending when closing the case flips the connectors off the pin headers.

[Blatboy]

Hi,

my recommendation is to use the following, easy and clean:

http://www.reichelt....0e328e8b2424f6b

I'm trying to figure out what this part is... I can't seem to figure out what it would be called when searching for it on Mouser or Jameco. Any suggestions for terms to look for or perhaps a link?

Thanks.

[Hawkeye]

I'm trying to figure out what this part is... I can't seem to figure out what it would be called when searching for it on Mouser or Jameco. Any suggestions for terms to look for or perhaps a link?

You´ve got a few options:
http://www2.mouser.c...1z0wxosZ1z0wxp7

My choice would be to solder the cable to the baseboard side (eg solder it to normal headers, then use shrink tube to protect the individual pins from touching each other), and attach/crimp a plug to its end. Then use a rectangular socket on the cs board, the link above lists a few plug/socket alternatives for eight pins with 2.54mm spacing... be aware that there is not much room though, the smaller the better .

I like these sockets, for example, but you also need corresponding plugs with crimp pins, ofc
http://www2.mouser.c...UNWgEEmG64gM%3d

Bye,
Peter

Edited by Hawkeye, 24 April 2012 - 13:19.

[Blatboy]

Thanks!!!

[Blatboy]

I like these sockets, for example, but you also need corresponding plugs with crimp pins, ofc
http://www2.mouser.c...UNWgEEmG64gM%3d

Bye,
Peter

If I use those parts on the control board, do you think there is room to use the non-right angle version of that (http://www.mouser.co...qNairr85cg%2bI=) on the main PCB? I think I'd prefer to do that than solder directly on the header and use heat shrink...

The plugs that go with both parts are here: http://www.mouser.co...xfbeWN9ZX56LQ==

[Hawkeye]

The referenced connectors might be a little bit too large, there is really not much room in that area of the case, especially if the connectors are upright and not angled - you could try with a temporarily screwed in CS board and the baseboard and a "dummy connector", with the size from the datasheet, to see if it would fit... On the other hand, I really would not make both ends detachable (it is a bit overkill imho), but of course, it is your choice...

Bye,
Peter

Edit: I don´t think these connectors are much bigger than orange_hands, they may just fit, if you have the coin, order two full sets of them and if it does not fit, you can always fall back to soldering to headers + shrink tube. Don´t forget the crimp pins themselves and a crimp tool, if you don´t have it yet... it is well worth the investment

Edited by Hawkeye, 03 May 2012 - 22:33.

[Blatboy]

Hmmmm. I suppose the only reason I'm shying away from soldering directly on the headers is my lack of experience w/heat shrink. We do have a heat gun in the basement, last time I checked. It would be cheaper... and I wouldn't have to mail order the heat shrink... as I can get that at a local store... tempting...

Decisions, decisions, decisions...

Thanks again for the help!!!!!

w

[Blatboy]

Hey Hawkeye,

In Step 14 you call for 4pcs M2.5 x 10mm screws (Reichelt SZK M2,5x10)... is there enough room in there to use 12mm screws? 10mm are hard to find around here without buying in bulk...

Thanks!


[EDIT] Actually, buying 100 is pretty darn cheap... so I'm just gonna do it.

Edited by Blatboy, 07 June 2012 - 20:43.