1050 drive mod with loose wire

[E474]

Hi everyone,

 

   I got this drive a couple of days ago, I always open them up before powering them up, and this one has a loose wire (the white one, in the second photo).

   I'm pretty sure it's part of a switch+light front panel assembly, and is part of the write-protect circuit, but I have no idea where it should go/be re-attached to.

   It comes from the J11 pins (on the underside of the PCB), which is in the schematic on Page 5-4 of the 1050 FSM (right page, bottom left corner of https://archive.org/details/1050FSMRebuiltAKH/page/n63/mode/2up).

   Can anyone take a stab at where I should try and reattach it?

   The wiring is a bit ropey, and it kind of looks like the wires are shorting on the underside anyway, though I'm not sure if the circuit has been altered as it's also connected to a resistor at the front of the PCB near the power switch (which has also seen better days).

   I'm quite reluctant to power it up as is, but I'm also a bit out of my depth on how to fix it.

   Incidentally, the advert (on Ebay, from a seller in Belgium) showed it working/powered up. Also guessing it's a Happy clone board, but waiting to fix the wire before testing it.

 

   Any help would be appreciated!

 

[TGB1718]

What a bodge job 😬

 

I would be tempted to note where all the wires go and then remove them all, by the

looks of it, there's no tracks been cut, so with it removed, it should work normally.

 

You could always refit it if someone can help if they recognise what it is.

[E474]

Hi @TGB1718,

 

   Thanks, that's not a bad idea, I might do that if no one else can figure out where the wire should go.

 

   Incidentally, I actually got 2 drives as part of the deal, the second one has the same setup, but a more complicated switch assembly as it has a Green and Red light setup (wires from J11 and the resistor at the front of the board). In this setup the cream wire (corresponding to the white wire in the first drive) goes into a big resistor, so that might be where it should go on the first drive (though I have no electronics skills, so this is guess work).

 

  Posting pictures of the other drive just in case it helps (and doesn't muddy the waters). By the way, I think this might be a clone Super Archiver, but I'm really not sure as it's a new one for me.

 

   

[xrbrevin]

theres no finesse in these mods..! its a shame really because they might be worth having if they didnt look so risky

J11 is for write protect, it is common for these to have LEDs to denote the switch position

[Houdini]

That soldering looks damn scary. Looks like lead-free solder too. The white wire isn't going to be the only one that pops off. I second the advice of removing it.

 

The picture below tells the tale. See how the joint circled looks bumpy like a pine cone? That's because the metals in a lead-free solder don't all re-harden at exactly the same time. That's what creates the bumps and also tiny little stresses in the joint. A lead-tin or lead-tin-silver alloy will create joints that are shiny like a mirror and strong enough to last as long as the machine they are in. It might be worth paying someone to properly redo the install for the mods. 

Edited December 17, 2023 by Houdini

[TZJB]

23 hours ago, E474 said:

Hi everyone,

 

   I got this drive a couple of days ago, I always open them up before powering them up, and this one has a loose wire (the white one, in the second photo).

   I'm pretty sure it's part of a switch+light front panel assembly, and is part of the write-protect circuit, but I have no idea where it should go/be re-attached to.

   It comes from the J11 pins (on the underside of the PCB), which is in the schematic on Page 5-4 of the 1050 FSM (right page, bottom left corner of https://archive.org/details/1050FSMRebuiltAKH/page/n63/mode/2up).

   Can anyone take a stab at where I should try and reattach it?

   The wiring is a bit ropey, and it kind of looks like the wires are shorting on the underside anyway, though I'm not sure if the circuit has been altered as it's also connected to a resistor at the front of the PCB near the power switch (which has also seen better days).

   I'm quite reluctant to power it up as is, but I'm also a bit out of my depth on how to fix it.

   Incidentally, the advert (on Ebay, from a seller in Belgium) showed it working/powered up. Also guessing it's a Happy clone board, but waiting to fix the wire before testing it.

 

   Any help would be appreciated!

 

 

 

 

 

 

 

 

 

 

 

 

The installation quality of the switches is very low as observers have said.

 

The first drive seems to contain a Happy Drive clone and the second drive has an unknown enhancement that has moved the U8 6810 SRAM chip to the expansion board. It is not a Super Archiver as there are no connections to the WD2793 and no U8.

 

Although the first drive would now be quite safe to turn on I would advise that you disconnect this 'write protect disable switch' and it's wiring. It seems to be badly installed and non-functional due to being a single pole changeover switch.

 

Note that the second drive has the double pole changeover switch normally required.

 

The black wire in the first drive illogically connects to J11 pin 3 (WRPT) and the white wire to J11 pin 4 (GND), although they seem to be shorted together at the board connection which should disable any write protection permanently! They are ready to fall off so just help them please.

 

This diagram shows the more usual arrangement for over-riding the disk write protect and replaces the existing J11 plug connector in order for the write protect operation to become a purely manual affair, disconnecting the on-board disk notch sensor. The +5V from J11 pin 1 is already supplied by R82 150R, so an extra 150R is optional. Not sure where this diagram came from but I am fairly sure the LED colours are the wrong way round!

 

Underneath the write protect override switch diagram is the circuit diagram of the original 1050 disk write protect circuit connecting to J11.

 

 

 

Edited December 18, 2023 by TZJB

[E474]

Hi everyone,

 

   Thanks very much, I didn't think the soldering was actually that bad, but perhaps on closer inspection it could be fixed up a bit.

 

I dug a bit deeper into the AA archives (used search), and found a few posts on this subject: 

and  

to name a few.

 

   I'm going to try and sketch out the current circuit with actual resistor values, and then see if I can figure out where the loose wire should go. I don't really want to throw out all the parts (even though they cost buttons), as I like the authentic bitd feel of things.

 

   However, I'm going to get the drive with the unknown mod working first, as there doesn't appear to be anything wrong with it. I'm wondering if the second switch is a toggle between a US-Doubler and stock ROM, though I'm not sure why it would need the extra wire to the PCB.

 

   Thanks again!

[xrbrevin]

1 hour ago, E474 said:

the second switch is a toggle between a US-Doubler and stock ROM

the lazer 1050 mod had a second switch to swap between it and the USD ROM - might be worth a look

[E474]

I tested the mystery mod drive (2nd drive above) with @Zolaerla's QuickOS disk detect routines - see: 

and it came up as an Unknown US Doubler, or an Unkown 180/1050, depending on the right side switch position.

 

@xrbrevin - the Lazer mod is a bit bigger than the mystery mod as the Lazer includes a 6502. My first post on AA was actually about my Lazer drive which had developed read/write problems, and also ended up with a loose wire problem. See: 

 

I think for the first drive with the loose wire, I will just un-solder the switch assembly as I think it will take me ages to figure out where it should be connected, and I would rather test the drive first.

 

Thanks again everyone for the help!

 

[_The Doctor__]

it isn't that difficult, the wire popped off the center pole of the switch...

[E474]

Hi @_The Doctor__,

 

   Thanks very much for the help, I'll take it as read that it's correct, but any chance of a simpleish explanation?

 

   I had a look for Single Pole Double Throw Switches (for example: https://www.elprocus.com/spdt-switch/), and it looks like the middle pin on the switch is the Common pin - and that's what the white wire should be soldered back on to. Is it one (electrical) path through the switch means the reading from the write protect sensor is always obeyed, and the other path through the switch means the sensor is ignored (either the disk is always writeable, or never).

 

   Looking at the second schematic in @TZJB's post above, J11 pin 1 is either GND at header position #4, or goes off to JP6/5 at header position #1 (I'm not clear how schematic connectors 1-4 on JP11 map to the headers on the PCB)?

 

   I'll try and solder up the wire this weekend (e.g. tomorrow), but I'd like to learn a bit about why the white wire goes to the middle pin on the switch too.

 

  I appreciate the help regardless!

[TZJB]

15 minutes ago, E474 said:

Hi @_The Doctor__,

 

   Thanks very much for the help, I'll take it as read that it's correct, but any chance of a simpleish explanation?

 

   I had a look for Single Pole Double Throw Switches (for example: https://www.elprocus.com/spdt-switch/), and it looks like the middle pin on the switch is the Common pin - and that's what the white wire should be soldered back on to. Is it one (electrical) path through the switch means the reading from the write protect sensor is always obeyed, and the other path through the switch means the sensor is ignored (either the disk is always writeable, or never).

 

   Looking at the second schematic in @TZJB's post above, J11 pin 1 is either GND at header position #4, or goes off to JP6/5 at header position #1 (I'm not clear how schematic connectors 1-4 on JP11 map to the headers on the PCB)?

 

   I'll try and solder up the wire this weekend (e.g. tomorrow), but I'd like to learn a bit about why the white wire goes to the middle pin on the switch too.

 

  I appreciate the help regardless!

 

If you disconnect the J11 header socket, the PCB is marked with pin 1. In fact each of the headers have their pin 1 marked on the PCB.

 

[TZJB]

Looking back at the first disk drive with the single pole changeover switch, the white wire goes to J11 pin 4 GND and the black wire goes to pin 3 WPRT so assuming the white wire is soldered back to the centre switch pin, with the switch one way, J11 pin 3 is grounded (WPRT is overridden) via the 150R resistor and the external LED lights via 5V from the yellow/pink wire and 470R resistor. With the switch the other way, the LED 470R resistor is grounded, the external LED is shorted out and WPRT is not overridden. Not very elegant but it looks like it might work.

 

Just to add that shorting out J11 pins 3 and 4 (or pin 3 to ground) has the same effect as a inserting a notched floppy disk into the disk drive i.e. writing is enabled. The LED in the original circuit physically sits over a mounted disk write enable notch and is illuminated by power from J11 pins 1 and 4. The light from the LED causes the opto transistor to conduct and shorts pin 3 to ground. When the disk notch is covered, this blocks the light preventing the transistor from conducting and write protects the disk.

 

I have now taken to disconnecting the original J11 connector completely and bypassing the original write protect circuit by replacing J11 with a new Molex 4 way socket (could have used a 3 way) and feeding the three wires to the DPDT overide switch and 2 colour LED at the front. This leaves no guess work as to whether the disk is write protected. And I don't need to notch a disk to use the flip side! The LED mounted above the switch also doubles as a power indicator due to the triple OS drive switch in the original LED space.

 

 

[E474]

Good news everyone!

 

   I soldered the white wire to the middle pin of the switch, and everything works! With the light off I can't write to a write protected disk, with the light on, I can write to a write protected disk. To be honest, I'm a bit skeptical that I actually want to have a drive that can ignore a write protect sticker, but I'm pleased that the drive works OK, and the switch is fixed.

 

   It actually looks like it is a Happy clone - I tried it with a QuickOS disk (see above), and it reported an Unknown U.S. Doubler (which it obviously isn't), but could also get the Happy Command Table, so I think that's what it is. I will try out the Happy and Lazer utility disks to see what they report, but the drive was quite willing to format a single density disk and write Dos files to it, so I'm counting it all as a win.

 

  I re-soldered the connectors to the header pins (thanks for the info on the pin numbering on the board - I saw 1s next to each block apart from J11 - but I figure it never hurts to ask), but is it worth putting something like hot glue on the wires to keep them apart, or , could I have wired up the middle switch pin from any ground, or did it have to be the ground next to the black wire (I'm assuming any ground would do)?

 

  Thanks again to @_The Doctor__ and @TZJB and everyone else who commented.

 

[TZJB]

13 hours ago, E474 said:

Good news everyone!

 

   I soldered the white wire to the middle pin of the switch, and everything works! With the light off I can't write to a write protected disk, with the light on, I can write to a write protected disk. To be honest, I'm a bit skeptical that I actually want to have a drive that can ignore a write protect sticker, but I'm pleased that the drive works OK, and the switch is fixed.

 

   It actually looks like it is a Happy clone - I tried it with a QuickOS disk (see above), and it reported an Unknown U.S. Doubler (which it obviously isn't), but could also get the Happy Command Table, so I think that's what it is. I will try out the Happy and Lazer utility disks to see what they report, but the drive was quite willing to format a single density disk and write Dos files to it, so I'm counting it all as a win.

 

  I re-soldered the connectors to the header pins (thanks for the info on the pin numbering on the board - I saw 1s next to each block apart from J11 - but I figure it never hurts to ask), but is it worth putting something like hot glue on the wires to keep them apart, or , could I have wired up the middle switch pin from any ground, or did it have to be the ground next to the black wire (I'm assuming any ground would do)?

 

  Thanks again to @_The Doctor__ and @TZJB and everyone else who commented.

 

 

That is great news. You are welcome.

 

The 1050 expansion board has enough chips to be a Happy clone and will be noticably faster when booting any disk due to the 6KB track buffer. However commercial disks may not boot due to protection used on the disk.

 

If you get a chance could you dump the ROM and upload please?

 

The Happy utilities should recognise the board as a Happy drive, which will hopefully pass the tests available from the Happy master boot disk. This disk also allows the setting of UnHappy mode in order to boot commercial disks.

 

So long as there is no melted insulation on the wires to the underside of the header pins there should be no need for hot glue. I normally twist the wires together and leave them floating, but I do use a header socket now. In my early attempts I did solder underneath J11 but used ribbon cable, and yes any ground can be used as a substitute for J11 pin 2 or 4.

 

However one would normally sleeve the wires to the switches to prevent short circuits and make it look tidy, but the decision will be yours.

Edited January 29 by TZJB

[E474]

Hi @TZJB,

 

   Yes, I'll try and dump the ROM at some point going forward (I wrote a utility called DUMP1050 for this, but I need to add a workaround to the Happy corruption bug fix for high speed code, which is still on my to-do list). 

 

    The PCB looks very similar to a Happy "clone" I picked up from The Netherlands (see below), which actually failed the Happy memory test (IIRC), but I think it was more to do with a hacked ROM than anything else (but I haven't checked so am not 100% sure).

 

   I think I will leave the wiring "as is", even though it looks a bit iffy, it will probably actually last a few more years (at least).

 

  Thanks again for the help!