9114 Controller Board Pic - 12v circuit?



#8

Tony (and anyone else who is still listening),

I have used the time away from home to mark a high-res picture of the controller board with the numbers for the individual parts. This might be of use to others as well, please feel free to download from here

Also, if possible I'd like to confirm that I have correctly identified the 12v PSU circuit with the 'monostable U106', 'MOSFET 105' and the related coils L101 and L102. For better identification I have circled them here for you. Maybe you can do a quick peek.

I was able to download a datasheet for the NE555N and will try to see if there are any oscillations on the Output pin. The result of which I will report. One thought I had that maybe the 100 Ohm resistor went, because we had so much amp flowing that the pico-fuse went. However via visual inspection the resistor looks fine. Anyway, I feel that over the last few days I have become a tiny bit better oriented on the PCB (yet it still looks like a miracle to me how you have been able to reconstruct the diagrams!)

Thanks a lot and - stay tuned!

Cheers

Peter
I will be back home tomorrow night at which point I hope to be in possession of my scope already for an interesting weekend ahead!


#9

Yes, I think you've found the right components.

Don't rely on a visual inspection for that resistor. Check it (with an ohmmeter). It's best not to assume anything is OK...

#10

Hi,

I have a 9114 circuit for spare parts lying somewhere in my "fix it all" box. If there is a special part you need, just say so. (only shipping costs).

Ronald


#11

Thanks, Ronald, that is super kind. I'll spend the weekend testing and let you know.

Greatly appreciate it!

Cheers

Peter

#12

Okay, I admitt of being slowly worn down by this board.

First, my scope did not come because it was sent to the wrong address or something. So it will come some time next week

Second, when I started the thing today, drive did not spin at all! Maybe something broke when I took it outside to take the digital pictures.

Okay, now here the measurement news:

1) As the drive did not spin at all, I re-did the selftest nr 1 and got the same (good) result that all internal chips like Ram, Rom, etc seem to be fine

2) On U106 I measured the following voltages:
1 - GRND - 0
2 - Trigger - 5.24
3 - Out - 2.42 (which is what you expected...)
4 - Reset - 5.90
5 - Ctrl Vol - 3.94
6 - Thresh - 1.30
7 - Discharge - 1.30
8 - Vcc - 6.11

There was no oscillation visible on my Ohmmeter, yet, as I mentioned, the scope was not here so no pic...

3) I measured also on Q105 and got 0 on ground and 6.11 on one side and 0.024(!) on the other

4) I measured the 100 Ohm resistor and it checks out.

5) I also check the amp again and now it draws much less, maybe 0.5 or so. Which I guess makes sense if the motor is not running at all...

Okay, I'm not sure what the next steps are, I'm a bit disenchanted that the drive now does not turn at all anymore...

Anyway, please let me know if all of this still points towards a broken Mosfet Q105 or any other ideas...

Your's faithfully

Peter


#13

Tony,

You will not believe it, yet the 9114a works again (at least outside of its encasing and with the direct power supply. But all in its own time!)

Having been slightly dinged by the previous tries, I had packed away all the parts. Only to unpack them some 10 minutes later with 'let's have another go at this!'

1) I tried to unsolder the existing Q105, which I failed to do due to lack of a) experience b) a proper soldering iron and c) a proper way to hold the PCB in place while I try to unsolder

3) So I first built a make-shift way to hold the pcb in place. Then I clipped the existing Q105 and then pushed the stumps through with the iron and a thin tip. (I picture a very painfully cringed face over in the UK right now...)

4) I put a new Q105 in place (side-remark: when I had ordered the picofuses I had overlooked the minimum order-size so they canceled my order. When I wanted to re-order you had already mentioned that you think the Q105 is broken so I added that to the pico-fuse order which got me over the minimum order size). It was such a hack-job that I myself felt badly about it. But in the end I had something that looked like connections on the new Q105

5) I turned things on now, only to be greeted with a fault light on and no turning of the motor whatsoever. However, I started with the measurements again and this time I did get the 12V where I expected it according to your diagrams. Hmmm, something was clearly different (and better) than before. So why still no piep from the drive??

5) Then I realised that the HPIL cable and the disk-motor cable both have 4 pins and fit into each others male counterparts on the PCB. Turns out, I had the disk connected to the HPIL plug on the PCB... Dooh. No wonder it did not spin. So I fixed that and connected all to its proper place.

6) You can imagine my cry of joy when the drive went on, did it self-test and the fault light went out! Unbelievable!!! I did some more test, like formatting a disk, writing a file to it and reading it back, all successfully. Such simple joy!

Now, I know, I am not fully done yet, I still need to get the cover in place and there was some shorting or the like going on there beforehand. And I have to fix the battery-charging circuit and make it work with the battery. Yet I am quite a happy chap right now.

Let me be clear here, for all intense and purposes, Tony fixed that drive, not me! I merely was the across-the-atlantic-remote-controlled extended arm of yours. And without ever laying eyes on the board, not to speak of making a single measurement yourself, you nevertheless figured out which part was broken!

I learned a great deal about the 9114 and had a lot of fun and now even some good old fashioned satisfaction. Thank you very much indeed!

Now I will happily go to bed.

All the best

Cheers

Peter


#14

Quote:
Tony,

You will not believe it, yet the 9114a works again (at least outside of its encasing and with the direct power supply. But all in its own time!)


Excellent!

Quote:

Having been slightly dinged by the previous tries, I had packed away all the parts. Only to unpack them some 10 minutes later with 'let's have another go at this!'


Alas I know that feeling all too well. I leave a repair/design/whatever and go to bed, only to get up 10 minutes later, turn on the soldering iron again, and carry on well into the early morning....
Quote:

1) I tried to unsolder the existing Q105, which I failed to do due to lack of a) experience b) a proper soldering iron and c) a proper way to hold the PCB in place while I try to unsolder


What have you got against step 2 ;-)

Quote:

3) So I first built a make-shift way to hold the pcb in place. Then I clipped the existing Q105 and then pushed the stumps through with the iron and a thin tip. (I picture a very painfully cringed face over in the UK right now...)


No painful looks from me, I can assure you. You wanted to save the PCB, that's by far the most valuable part. I've known to clip the pins off a DIL IC and desolder them one at a time to protect the PCB (althought I must say I desolderd all 32 RAMs without clipping the pins when I upgraded the memory in my HP9816 recently...)

Quote:

4) I put a new Q105 in place (side-remark: when I had ordered the picofuses I had overlooked the minimum order-size so they canceled my order. When I wanted to re-order you had already mentioned that you think the Q105 is broken so I added that to the pico-fuse order which got me over the minimum order size). It was such a hack-job that I myself felt badly about it. But in the end I had something that looked like connections on the new Q105

5) I turned things on now, only to be greeted with a fault light on and no turning of the motor whatsoever. However, I started with the measurements again and this time I did get the 12V where I expected it according to your diagrams. Hmmm, something was clearly different (and better) than before. So why still no piep from the drive??

5) Then I realised that the HPIL cable and the disk-motor cable both have 4 pins and fit into each others male counterparts on the PCB. Turns out, I had the disk connected to the HPIL plug on the PCB... Dooh. No wonder it did not spin. So I fixed that and connected all to its proper place.

6) You can imagine my cry of joy when the drive went on, did it self-test and the fault light went out! Unbelievable!!! I did some more test, like formatting a disk, writing a file to it and reading it back, all successfully. Such simple joy!


Excellent!

Quote:


Now, I know, I am not fully done yet, I still need to get the cover in place and there was some shorting or the like going on there beforehand. And I have to fix the battery-charging circuit and make it work with the battery. Yet I am quite a happy chap right now.


I wonder if the short-through-the-cover or whatever is what blew the fuse in the battery pack. I don't think it would have damaged Q105, though. You want to look very carefully for trapped wires on the disk drive mechanism.

Quote:

Let me be clear here, for all intense and purposes, Tony fixed that drive, not me! I merely was the across-the-atlantic-remote-controlled extended arm of yours. And without ever laying eyes on the board, not to speak of making a single measurement yourself, you nevertheless figured out which part was broken!


To be fair, you made some measurements and reported the results. Without knowing it was certainly a problem in the 12V PSU circuit, I would not have homed in on Q105.

As to why I went for Q105, you can call it 'experience' (with SMPSUs, not the 9114 in particular) or 'good luck' :-).

Quote:

I learned a great deal about the 9114 and had a lot of fun and now even some good old fashioned satisfaction. Thank you very much indeed!


All I can say is that I am pleased another piece of fine HP calculator hardware is running again!


Possibly Related Threads...
Thread Author Replies Views Last Post
  HPSWAP Archive and the 9114 Dave Frederickson 0 236 12-01-2013, 01:43 AM
Last Post: Dave Frederickson
  HP-65 short circuit Ignacio Sánchez 2 382 10-22-2013, 08:27 AM
Last Post: Ignacio Sánchez Reig
  Need manual for HP 44464a (a 3421a I/O board Alan Sciacca 1 234 03-12-2013, 03:31 AM
Last Post: Diego Diaz
  HP-65 logic board repair - help required Alberto Fenini 1 287 02-17-2013, 06:39 PM
Last Post: John Robinson
  Hp85 PRM-85 board Roe Peterson 2 329 12-08-2012, 12:00 PM
Last Post: Roe Peterson
  9114 drive "rod knock"? BobVA 2 263 10-05-2012, 10:13 AM
Last Post: BobVA
  Can my CV take a CL board? Les Wright 5 473 06-03-2012, 08:33 PM
Last Post: Les Wright
  OT: looking for pic of an ARISTO M27's backside Mike (Stgt) 7 529 01-26-2012, 11:48 AM
Last Post: Maximilian Hohmann
  Circuit for HP3421A Data aquisition Barrie Carruthers 4 388 01-06-2012, 07:14 AM
Last Post: RamLab
  HP 9826A HPL ROM board part number David Ramsey 2 292 12-17-2011, 10:12 PM
Last Post: David Ramsey

Forum Jump: