What is this 1050 board?

[Nermal]

Hi all, as you may know from my previous post 1050 my US Doubler seems to be misbehaving and not reading anything other than SD.

 

One of the suggestions I got was to try and replace the FDC chip,   In my spare (and very broken 1050 I bought from a car boot sale when I connected it something on the board started smoking) didn't have one it had an empty socket but it did contain this.

 

I think it was called a LAZER,   would this allow the reading of US Doubler disks?   It's in such poor shape though I don't know if I would risk it killing the working 1050 completely.  

 

What would you recommend? I see there is a Happy 1050 in stock on 8BitClassics would that be able to read (and archive to ATR) US Doubler disks?

 

Many Thanks in advance.

 

Nermal

 

 

 

 

 

 

[Nermal]

P.S. 

 

If I did give it a clean and try it out, do you know which side way round it would go, I would imagine that the part that said component side would be the correct way up when looking from the front of the drive.

 

Thanks  

[_The Doctor__]

the board needs solder reinforcing for the corroded traces after cleaning...

my concern is you said you tried it without knowing which way it was to be inserted... you may well have already damaged it further.

the chips on top have the notch on the pin one side. I hope you cleaned the header pins till they shined again.

Edited June 5, 2022 by _The Doctor__

[Nermal]

Hi Doctor,

 

No I've not fitted it, I don't want to break my only working 1050.   Thought I'd take advice first lol

 

 

 

 

[E474]

A Lazer drive will definitely read US Doubler disks, both support Double Density (256 byte sectors, 720 sectors per disk). The Lazer board is a hacked Happy board, there is an ATR I posted with utilities specific to the Lazer in another thread, which should show up in a forum search.

 

You should be able to figure out which way round the board goes by figuring out which pins on the 6502 are +5V and Ground, then seeing where the traces go to the pins that go to the board connector, and matching them against the pin outs for the 6507, which is the socket that the board will go into. It's a bit tedious, but I can't think of a reliable way otherwise. Just try Googling for the 6502 and 6507 datasheets (unless anyone knows a simpler method)?

Edited June 5, 2022 by E474
Typo

[TGB1718]

7 hours ago, E474 said:

unless anyone knows a simpler method

Spot on, just identify +5V and 0V lines on the mainboard socket and the connecting pins on the board

 

[guus.assmann]

Yes, it can be a lot more simple.

The 74LS139 has GND on pin 8 and VCC on pin 16.

So just insert the board and make sure the chrystal on the 1050 is not in the way.

Then, check for continuity between pin 8 of the 74LS139 and anothet TTL chip on the 1050 board.

Or just follow the trace from the 74LS139 pin 8 to the pin header, wher pin 2 should be GND.

Alternatively, follow the trace from pin 16 of the 74LS139 to pin 40 of the pin header. Pin 28 of both Ram and Eprom are also VCC.

And pin 14 of Ram and Eprom are GND.

 

Looking at the picture of the bottom side, the "fat" trace is GND and goes to pin 2.

This means that this side of the board needs to face to the front of the 1050.

So in the picture, the top side of the PCB (looking at the bottom of the PCB :-)  ) should face to the front of the 1050.

 

The side where it reads "components" in the copper trace, should face to the back of the 1050.

BR/

Guus

Edited June 5, 2022 by guus.assmann
Addition to tekst

[+nasty niff]

the board will only fit in one way

 

[guus.assmann]

If you push hard enough........

 

Also, the board goes in place of the 6507 processor.

However, the Eprom also needs to be removed. This is obvious to the "expert" but I thought I should mention it....

BR/

Guus

 

Edited June 5, 2022 by guus.assmann

[Nermal]

5 hours ago, guus.assmann said:

If you push hard enough........

 

Also, the board goes in place of the 6507 processor.

However, the EPROM also needs to be removed. This is obvious to the "expert" but I thought I should mention it....

BR/

Guus

 

 

Hi thanks for all the help,   I'm in no way an expert!

 

I removed the USD piggy backed RAM? (MCM6810P) and replaced it back with the original single one out of the broken drive.

 

Removed the EPROM and installed the (Happy / Lazer clone) board.

 

Power on and  I have a Happy 1050

 

Swapped out the WDC chip and all running fantastic.

 

Thanks for the help once again.

 

[BillC]

17 minutes ago, Nermal said:

Swapped out the WDC chip and all running fantastic.

From what I understand the drive should be recalibrated if it's the FDC(WD2793) chip you replaced.

 

 

[+nasty niff]

Does it pass the ram test?

[+Nezgar]

On 6/5/2022 at 3:34 PM, Nermal said:

Removed the EPROM and installed the (Happy / Lazer clone) board.

 

Power on and  I have a Happy 1050

Run the option 2) diagnostic. The result of the RAM test will show which version of the 1050 happy ROM you have: 'PASS' for v1 and 'Pass' for v2, or possibly a failure for any other modified version...

 

I believe "laser" upgrades I've seen previously here on the AtariAge forums had the v1 ROM. V1 does not support the UltraSpeed protocol on power-up, and must be enabled with the utility disk. It also probably doesn't exhibit a bug where sectors are currupted with unbuffered single density disk writes.