Landover BBS - Commodore 128 & PET - since 1987

So far the guy has been responsive and claims he has hundreds in stock.  Just placed my order, fingers crossed...

Thanks!  Sent them an email...

Do you mind me asking where you're getting those chips from?  I'm in the market for a couple of chips from my 128DCR as well (8502R0 and 390059-01 chips).

Thanks

Hi -

Just getting back into the C= scene, and I have a variety of systems here I'm getting running (C64C, C128, C128DCR).  I'm hoping the main system I use will be the C128DCR, but there's a chance I might have to fall back to a C128 if I can't get the 128DCR running 100%.

I'm looking at buying some stuff from go4retro.com.  I have a few questions I'm hoping someone can answer:

 - Regarding the ZoomFloppy, I see there is an option to add an IEE connector.  What is the IEE connector, and what would I use it for?

 - Regarding the UIEC, I'm a bit confused regarding the Basic vs Deluxe daughterboards.  I may be wrong, but my understanding is that the Basic version attaches via an IEC cable and also takes power from the cassett port.  I also believe that the Deluxe version attaches to the cartridge port instead and does not need the cassette port for power - but does still need the IEC cable.  Is this correct?  I see that the Basic version is recommended for the C128DCR because it's attached with cables and can be moved to the front of the machine, but is there any reason I'd want easy access to it?  Because of the "button for swap list navigation"?  Is this used to swap disks, or for something else?

 - Does anyone make a nice enclosure for the UIEC?  I was hoping to see something on Shapeways.com but did not.  I guess I could hack it into some kind of project box, but I'd prefer to pay someone to do a better job than I could.    I'd rather not modify the computer's casing in any way.

 - If I wanted JiffyDOS but did not care about speeding up the floppy drive, could I simply order the C128 version for my C128DCR?  I assume with that version I would get the JiffyDOS speed benefits when using the UIEC, but not with the internal 1571 - am I correct?  What is the included switch for, in case I want to disable JiffyDOS?

 - I'm a bit confused on the separate "RoM Overlay" images available for JiffyDOS.  So, I buy the chip itself but need to load the image onto it?  How is that done?

Sorry for the newb questions, but wanted to make sure I understand everything before ordering.

Thanks in advance!!

Thanks for the info on that R5 resistor.  If anyone has the ability and/or time to post up a close up of the one on their board I would really appreciate it.

Thanks!

Right... But even if it is 110, is it possible that it's wrong and the service manual is right?  I've seen Amiga capacitors in backwards or worse from the factory....

Ugh!

Here are a couple more pics of the resistor, sorry for the bad quality - couldn't get my phone camera to focus too well.

As you can see, whether it's "leaking" or not it does seem damaged - especially on the end closest to the R5 marking - it appears busted open.

I'm no electronics guy, so don't understand the function of the resistor or what effects a damaged one could have - but common sense is telling me I should replace it if it looks like that.

Thanks for the replies.  The service manuals I found showed a different layout board, apparently the 128 and 128D - but none looked like my 128DCR.  I saw those schematics, but I might as well be trying to read Japanese.  I did locate R5 on there, but did not see anything indicating a value for the resistor.

A buddy of mine (Mech from www.a4000t.com - great guy!) was able to locate a scanned copy of SAMS Computerfacts for the 128D, which does match the layout of my board.  According to that document R5 is a 27 OHM 3W 5% Carbon Film resistor.  Looks right to me, though the bands on the original resistor seem to have lost their color due to heat/age so I'm going to have to trust the document.

Maybe it's not leakage, but it does look like it's damaged or has somehow popped open.  I'll have to take and post up an image from another angle where the resistor looks worse.  Whatever it is it doesn't look good to me.  Perhaps it's not the cause of the issue, but at this point it's my best guess and probably should be replace either way. 

As for troubleshooting my issue further, I do have a couple other standard 128s I could try swapping some chips with I guess, wherever they match up - but no other 128DCRs to try swapping power supplies with.  I don't see any leaking capacitors.

I do think I can replace it without ruining it - I'm an amateur solderer for sure, but getting better.  I have replaced some blown resistors on my recently acquired Amigas, motherboard power socket, leaking battery, etc.... successfully.

Hi -

Trying to go through my "new" Commodore 128DCR, having an intermittent issue booting into 128 mode.  I noticed a resistor on the board that appears to be blown/leaking.  See attached pic:

Not sure if it's related to my issue, but it does look like it should be replaced.

Trying to find out the value of this resistor, but I only seem to be able to find C128 and C128D service manuals, and the board layout does not seem to match.

Can anyone point me in the right direction?

Thanks!

OK, I ended up replacing it with a 9-pin M-F straight through cable I had kicking around and I was able to get it to sync.

As for the other cable, pin 8 was the one missing which is labeled Horizontal Sync in the diagrams I can find.  Not sure why it worked on the 128 but not the 128D, but I'm just going to trash it at this point.

The 128D was behaving fine during my quick testing, but today I went to play more and once again it will not boot into 128 mode - only 64 mode.  I'm sure if I let it rest a while it will start booting.

Kind of sad... of course I'll probably use it 99% of the time in 64 mode, but really wanted a fully working 128D.

Anyone have any suggestions on what I could try replacing?

Thanks guys...

Wellcome in the world of C128 users!

Thanks! 

That's strange. Could it be a NTSC/PAL problem?

Don't think so, everything should be NTSC....