Restoring a PAL 600xl - advice needed

[flashjazzcat]

U1MB is snug but no trouble:

 

 

[xrbrevin]

I would suppose any UK retro computer site or even ebay would be an easy place to find AV cables. I just make my own up tho.

Its easy enough to do. If you hack up an RCA phono lead and an SVHS lead you can make two in one go! solder them into a 5-pin DIN plug using the following diagram:

[flemingt]

6 hours ago, xrbrevin said:

I would suppose any UK retro computer site or even ebay would be an easy place to find AV cables. I just make my own up tho.

Its easy enough to do. If you hack up an RCA phono lead and an SVHS lead you can make two in one go! solder them into a 5-pin DIN plug using the following diagram:

Brill, though for the time and effort I think I found one on ebay. I'll see what the seller comes back with regarding compatibility.

 

12 hours ago, flashjazzcat said:

U1MB is snug but no trouble:

 

 

Good video series! Wow, notching the board, brave! It also looks like I'd need a finer tip soldering iron for that via work, but that's something new to try. I presume the RF shield doesn't fit after that.

 

I'd probably just knock up a 3D printed adaptor and hook it over the mainboard. I have some ideas, based on some raspberrypi cases I've been printing.

 

would something like this work for the 64kb upgrade?

https://www.ebay.co.uk/itm/5PCS-Dynamic-RAM-IC-NEC-DIP-18-UPD41464C-10-D41464C-10-UPD41464C-D41464C/162784727849?hash=item25e6b9d329:g:VhYAAOSwovNaIkQx

 

Edited August 12, 2020 by flemingt
question RE RAM chip supply

[flashjazzcat]

2 hours ago, flemingt said:

Wow, notching the board, brave!

No risk as long as you're not cack handed. This installation video follows the method advocated by Candle, the U1MB's designer.

2 hours ago, flemingt said:

It also looks like I'd need a finer tip soldering iron for that via work

That's a Hakko T12-BC2 tip.

2 hours ago, flemingt said:

I presume the RF shield doesn't fit after that.

No, it doesn't fit, but the shield is largely useless anyway. You can still fit the bottom shield if you feel like it.

[flemingt]

thanks @flashjazzcat

OK, time to put my money where my mouth is...

since I'll be after the U1MB anyway, instead of the 64kb upgrade per above, would it make more sense to use this:

https://lotharek.pl/productdetail.php?id=291

so I can get them both at the same time and possible save on some shipping costs?

 

while I'm at it I can pick up the AV cable and an SIO loader from the same store...

 

thus spending more time and money on the system than it's probably worth ? 

[flashjazzcat]

Personally I'd do the 64K mod using the two DRAMs since it's so easy and cheap, but it's up to you.

 

[flemingt]

3 hours ago, flashjazzcat said:

Personally I'd do the 64K mod using the two DRAMs since it's so easy and cheap, but it's up to you.

 

yeah, you're right. I was being lazy. I ordered a pair from ebay out of the UK so they should be here in a week or so.

[flemingt]

ordered a bunch of stuff from lotharek.pl, now I wait...?

[mdivancic]

On 8/12/2020 at 3:35 AM, flemingt said:

I'd probably just knock up a 3D printed adaptor and hook it over the mainboard. I have some ideas, based on some raspberrypi cases I've been printing.

I’m working on one for the 800xl myself. May be finished this weekend if the family cooperates...

[flemingt]

that's great @mdivancic - I'm more than happy to share ideas and designs. Do you have any dimensions of the board? thickness, overall dimensions, hole spacings? I can start sketching something up. I have an idea that should be printable with no supports.

 

edit: something like this, but once I measure or get dimensions for the U1MB I'll refine further.

Edited August 13, 2020 by flemingt
adding CAD

[xrbrevin]

lotharek products are very good, you wont be disappointed!

[mdivancic]

12 hours ago, flemingt said:

that's great @mdivancic - I'm more than happy to share ideas and designs. Do you have any dimensions of the board? thickness, overall dimensions, hole spacings? I can start sketching something up. I have an idea that should be printable with no supports.

Not much developed yet, just an idea. My printer was down for about four weeks awaiting parts so I’ve been on hold. My idea is similar to yours. Main difference I see are that I’ll be using heat set inserts to hold the board on. On the 800xl the U1M is more centrally located so I’ll be taking advantage of some of the fasteners that hold the main board and the RF shield on to secure my mount to the computer. No cutting or drilling holes. I’ll share more this weekend. 

[mdivancic]

Here's the prototype which will be test printed later today. Blue objects will be subtracted before print. I'm going to start a new thread on this once I have something.

 

 

[flemingt]

Looking good. Conceptually very similar. I took a simpler approach to mine, partially due to CAD skills, but also to minimise support structure requirements.

 

Eager to see how this turns out.

[flemingt]

DRAMS came in the post today and the U1MB, AV cable etc are due Thursday. Weekend project sorted!

 

Some questions about the AV port on the PAL 600xl. Is it monochrome with mono audio? Are there any mods required to make best use of that port?

[manterola]

If I remember correctly the PAL has the monitor port but the Chroma signal (color) is not connected. I connected it to the DIN 5 using a wire and you also need to cut a trace under the motherboard, because the DIN5 pin used was grounded.

I discover that the 600XL PAL output (svideo) was not that bad (and I did not want to spend more money) so I settled on using the monitor output just like that (as oppose to installing the great UAV rev.D board).

edit: ah! and the audio is mono, yes.

Edited August 18, 2020 by manterola

[flemingt]

Thanks, I'll do some more research! 

[manterola]

I opened my 600XL pal and this are mods I did. 

I guess I used parallel 150 ohms resistors to get the standard 75 ohms output resistance. 

Regards, 

 

 

[flemingt]

The top image is your RAM upgrade? I've seen some other 3 wire setups that don't desolder the resistor and they remove a chip and put a jumper cables into the socket... Interesting.

 

Each of those heat shrink cables have pairs of resistors in? I'll need to check my parts bin or see about scavenging from old hardware to see if I have anything that I can make work.

[manterola]

I followed this:

However I removed c109 only not the other components, to keep the composite working. 

I used 150ohms parallel twice for chroma and lumma

 

[flemingt]

So I've been busy this morning. I actually had some of the required resistors in stock (but no heat shrink) to do the video mod. The c109 capacitor fell apart when I was desoldering it.

 

I also did the RAM upgrade and soldered in the pickups for the U1MB upgrade.

 

Tomorrow I'll have a look at designing a bracket for the U1MB board.

[flemingt]

Instead of faffing with cable lengths, I'll probably install it like this. Now to work out some brackets.

[mdivancic]

@flemingt What does it look like under the U1M?

[flemingt]

Clearance looks pretty good. 

Prototype bracket came out well too, no supports needed for printing and I reused some of the RF shield nuts and screws.

Definitely room for improvement in the design though.

More than happy to share, if anyone is interested.

[mdivancic]

Nice design. Are you not worried about flex because one side is not supported? Please post the STL here for others. Also if you want I can add it to my Thingiverse post so these are all in one place. Now we need designs for the XE’s.