Atari 1050 Drive - Think I made it worse...

[Toby Rieper]

Hi,

I've been working on my 1050 drive for the use with my 800XL. I had the 'boot error' problem, time and time again. I cleaned the switches and the I/O ports as well as held in the specific key on the 800XL while booting to bypass basic. I checked the regulators Q7 & Q8 and replaced as they got quite hot. I also replaced the 3 big capacitors on the board as they were out of spec and had a high esr rating. Just for good mesaure I replaced Q6 with a working part.

When I came to re assmble (i took photos before hand) I put it all back together and now it just turns on, the head moves back and forth between the paking sensor the nout. Before at least it tried to read the disc. I've cleaned the head of the thing and checked votltage across TP14/15. It seems as if the motor doesnt kick in at all. Could I have made it worse? I checked all my Cap orientations and my soldering is good so I'm bot sure what I've done. Aslo which way do I oreintate the header that goes from the head to the front of the unit? I think it's red wire towards the back of the unit? I have tried both ways but nothing. 

If anyone could point me in the right directon that would be amazing. I don't have a scope but have a decent voltmeter and a logic probe :) I have attached photos of my work and here is a link to the video of the drive in action,

 

https://photos.app.goo.gl/mBstQcV4ucLCk4vGA

 

Hopefully I can get this sorted and not end up tearing my beard out!

 

[xrbrevin]

head connector looks the wrong way round - the red wire goes to the front usually

[Toby Rieper]

Just now, xrbrevin said:

head connector looks the wrong way round - the red wire goes to the front usually

Thank you, I have put that the correct way round still the same

[Gunstar]

Yep, and though I have worked on 1050's quite a lot, I often plug that in backwards myself!

 

Wires on the J9 connector don't look to healthy, especially the ones with the purple shrink tubing?

Edited November 3, 2019 by Gunstar

[xrbrevin]

does the motor spin when the drive is powered on?

if not i would check the J1 plug - that is what connects the motor to the board.

J14 is 'diskette enable' so the drive knows when a disk is inserted. if this is amiss then the drive motor wont spin when a disk is put in.

of note, your J9 plug should be marked J10. those pins are for the zero sensor.

Edited November 3, 2019 by xrbrevin

[Toby Rieper]

35 minutes ago, Gunstar said:

Yep, and though I have worked on 1050's quite a lot, I often plug that in backwards myself!

 

Wires on the J9 connector don't look to healthy, especially the ones with the purple shrink tubing?

Hi this has been worked on before, there wires that I have re soldered yesterday. The old job just used sticky tape I have checked J1 and the connections to the motor are good. Also I put my multimeter probes in the pos and neg of the motor terminals on J1 and when the drive switches on it goes up to about 3volts while the head is moving forward and back then back to nil.

[+Nezgar]

In your video, you don't leave the drive on long enough to see if the drive busy light goes off after it idles out after about 3 seconds. The light on the mech normally lights only when the motor is also spinning.

 

Also, with no disk in drive, after that initial poweron idle timout, and busy light turns off, just closing the door should cause the light and motor to turn on again for another 3 seconds or so.

 

I also question the spliced/heatshrinked wires on that one jumper J9. Also do you have another 1050 you can temporarily swap the mech into? Just to see if the mech's motor is not burned out. (don't put the good mech in the unknow drive)

[Toby Rieper]

18 minutes ago, Nezgar said:

In your video, you don't leave the drive on long enough to see if the drive busy light goes off after it idles out after about 3 seconds. The light on the mech normally lights only when the motor is also spinning.

 

Also, with no disk in drive, after that initial poweron idle timout, and busy light turns off, just closing the door should cause the light and motor to turn on again for another 3 seconds or so.

 

I also question the spliced/heatshrinked wires on that one jumper J9. Also do you have another 1050 you can temporarily swap the mech into? Just to see if the mech's motor is not burned out. (don't put the good mech in the unknow drive)

Hi the light does go off but it is quite dim. Didnt seem that dim before when it was all working correctly albiet boot error. As sson as I turn the unit on there is no signs from the motor. No, I wish I did just got this and a busted 1010 drive. In my previous post i did check pos and neg of the motor and it went up to 3 volts as it powers up and go through the motions. Is this too low? ** I also checked my 'J9' connections and theya re all good

Edited November 3, 2019 by Toby Rieper
Update

[+Nezgar]

48 minutes ago, Toby Rieper said:

In my previous post i did check pos and neg of the motor and it went up to 3 volts as it powers up and go through the motions. Is this too low? ** I also checked my 'J9' connections and theya re all good

The motor should be getting 12V DC. 3V is not enough to turn it. Maybe check your 7812 regulator output voltage again, and at different points? Although I believe you indicated you replaced it. I've had a drive where those very small caps fail and were causing a short circuit on the 12V rail... (making the 12v regulator get VERY hot within 10 seconds or so..) The other 3 wires to the motor will be tach out and ground. The voltage will actually be variable from 12V depending on the tach feedback ...

[xrbrevin]

have you had any of the ICs out? a disturbed RIOT or ROM might give these symptoms

[Mclaneinc]

The VR on the back plate does not look like the top half has been soldered and a number of the joints look seriously dodgy, I'd reflow many of those from the first photograph..A clean up of the board and news photo's could help, more directly over the PCB.

 

Always clean the board up, it makes spotting track breaks and dry joints so much easier..

[Toby Rieper]

12 minutes ago, Mclaneinc said:

The VR on the back plate does not look like the top half has been soldered and a number of the joints look seriously dodgy, I'd reflow many of those from the first photograph..A clean up of the board and news photo's could help, more directly over the PCB.

 

Always clean the board up, it makes spotting track breaks and dry joints so much easier..

Hiya, thanks yeah i will clean up the board and reflow the joints Didnt spot that one on the regulator. I have to order another 7812 as I accidently shorted it!

[xrbrevin]

i thought atari were being tight with their solder... 😬

[Toby Rieper]

Oh on the regulators you mean? Yeah I did those.... They looked great from the bottom of the board...

I'll do better next time

[Mclaneinc]

Don't take it to heart, doing repairs / work on boards can be mind numbing, I'm grateful I don't need to do it these days, its so easy in the midst of 50 joints to miss one on both sides of the board simply because you didn't flow enough in a bid to move on to the next joint.

 

FJC on here posts video's of his repairs and installs, he must have the patience of a saint

 

Oh and one of those cheap USB scopes is a really handy purchase, especially if like me your eye's are going. When I mean cheap I'm talking 7.00UK, its more than adequate for normal sized PCB work but a more expensive one for mini surface mount work.

 

Again, grateful I don't have to work on those...

[xrbrevin]

just out of interest, the zero sensor header is labeled J9 on the Indus GT drive and J10 on the 1050

[+kheller2]

On 11/3/2019 at 2:57 PM, Toby Rieper said:

Hiya, thanks yeah i will clean up the board and reflow the joints Didnt spot that one on the regulator. I have to order another 7812 as I accidently shorted it!

Forget the spacer against the heat sink?   

[Toby Rieper]

On 11/3/2019 at 8:47 PM, Mclaneinc said:

Don't take it to heart, doing repairs / work on boards can be mind numbing, I'm grateful I don't need to do it these days, its so easy in the midst of 50 joints to miss one on both sides of the board simply because you didn't flow enough in a bid to move on to the next joint.

 

FJC on here posts video's of his repairs and installs, he must have the patience of a saint

 

Oh and one of those cheap USB scopes is a really handy purchase, especially if like me your eye's are going. When I mean cheap I'm talking 7.00UK, its more than adequate for normal sized PCB work but a more expensive one for mini surface mount work.

 

Again, grateful I don't have to work on those...

Thanks for your positive input .:) I'll get back to it with a fresh pair of eyes. Maybe if I resolder the new 7812 all nice it will be fine. I thought I had a spare but I mis identified a 7812 and instead out another TIP110 in its place.

I was just tired, thankfully all I damaged was the TIP110 and it was a spare. 

4 hours ago, kheller2 said:

Forget the spacer against the heat sink?   

Hiya I checked the spacer and q6 is isolated from the grounding shield 

10 hours ago, xrbrevin said:

just out of interest, the zero sensor header is labeled J9 on the Indus GT drive and J10 on the 1050

I think that was from a previous repair that I haven't done. They probably used the header off that?

I believe this  sensor is installed correctly as it hasn't had any problems with the drive. This problem must be a power issue. I will let you all how I get on after receiving the replacement parts

[xrbrevin]

just looking at your first image closely, have the 2x diodes between the big caps been replaced? they look like theyre covered in goo/glap and mounted close to the PCB. in standard trim, these diodes are deliberately 'long-legged' in order to dissipate heat. if so, they may be worth checking

here is a pic of mine for reference:
 

 

Edited November 5, 2019 by xrbrevin

[xrbrevin]

2 hours ago, Toby Rieper said:

I think that was from a previous repair that I haven't done.

the mechs (tandon brand) are fully interchangeable so i wouldnt worry about it. its just an observation.

you may find that your disk latch lever is shorter as a result but its not an issue

[Toby Rieper]

On 11/5/2019 at 9:24 AM, xrbrevin said:

just looking at your first image closely, have the 2x diodes between the big caps been replaced? they look like theyre covered in goo/glap and mounted close to the PCB. in standard trim, these diodes are deliberately 'long-legged' in order to dissipate heat. if so, they may be worth checking

here is a pic of mine for reference:
 

 

Hiya thanks , I did a quick test of the diodes and they conducted current one way not not the other so I guess they work?  I'm working on the system tonight so will report my findings

A big thank you to everyone that has replied to my original post. 

[Toby Rieper]

On 11/5/2019 at 9:24 AM, xrbrevin said:

just looking at your first image closely, have the 2x diodes between the big caps been replaced? they look like theyre covered in goo/glap and mounted close to the PCB. in standard trim, these diodes are deliberately 'long-legged' in order to dissipate heat. if so, they may be worth checking

here is a pic of mine for reference:
 

 

Thanks for the pic. What diodes do you use? Can I use any shottkey diode or does it have to be a specific one? 

[Colleton]

On 11/3/2019 at 10:50 AM, xrbrevin said:

head connector looks the wrong way round - the red wire goes to the front usually

Yeah, this one is def the wrong way around.  I took pics before I installed my happy warp drive last week and can verify that you are correct.  I wonder if hooking it up backwards could have damaged anything?

[xrbrevin]

6 hours ago, Toby Rieper said:

What diodes do you use?

Atari_1050_Disk_Drive_Sams_Computerfacts_Technical_Service.pdf

1050FSM-Rebuilt - AKH.pdf

 

please see the 2x attachments. interestingly, they give different part numbers for these diodes (CR15 & CR16) but that means you have a choice! 🙂

both diodes are the same and you can use either 1N5392 or 1N4001.

i would advise you install them long-legged style as atari did originally.

 

can you see any other evidence of someone else's repairs? its always my first port of call for a dysfunctional item

[xrbrevin]

5 hours ago, Colleton said:

I wonder if hooking it up backwards could have damaged anything?

hopefully not, but its possible. ive never had it happen to me and i dont want to try it out..! hehe

in this instance tho and at this stage, the user is not getting any motor response so that needs sorting before the read/write head operation can be determined.