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justacruzr2

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About justacruzr2

  • Birthday 09/20/1954

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  1. Everything on both cards was replaced with new parts. And yes.
  2. That 4th drive is the exact same model. And I have tried that but no luck. I haven't replaced the resistor packs yet or the caps so I think I will try that first and see what happens. Fortunately I acquired (for free I might add) the new parts inventory of a TV and electronics repair shop that went out of business. He was going to just throw it all out and I asked him if I could have it. And it did include the Holy Grail of capacitors.....polystyrene caps. Almost impossible to find these days. These drives have 5 of that type on the main PCB. Somewhere along the line I'm going to hit the bad part.
  3. There was no difference with the Rev A (WD1773) card. So this definitely points to the drive. And I guess that the data separation resistor hasn't come into play yet. 2 nights ago I did a little more testing of the main PCB on the drive, comparing it to a 4th drive I have. I actually have 4 drives but the 4th drive never was in play because I bought it off eBay as a "AS IS for parts or repair". And that's exactly why I bought it...for parts. Well when testing one of the resistor packs, a 12 pin one, I found some interesting differences. On the 4th drive, putting the multimeter negative probe on the pin with the dot, as I moved from pin to pin, the meter showed consistent resistance and the readings would start out low and then increase to a point and stop. This told me that these pins are going thru caps and the caps are OK. On the drive we've been working with, the readings were much higher and they did not increase as if going thru a cap. So I'm thinking either the resistor pack is defective or there are one or more caps that are defective. Sound right? What do you think?
  4. Sounds like a reasonable conclusion. Yes, this board has 2 adjustable resistors and the one you may be referring to is called the Data Separation resistor. I have not adjusted it firstly because I thought I would first see if the drive would read data and see if I get an error message (maybe that's what's already happening as you say) and secondly, and I do have the datasheet and instructions on how to adjust it, it suggests using a scope. That's not cheap and I really wouldn't have any further use for it when done. So I thought what I might do is adjust it on the fly. And to do that I would have to get the drive to search long enough to see if turning the screw makes a difference. That's a bit tricky. You usually don't get more than about 3 or 4 seconds. And yes I also have the Rev A board as well. I think it did the same thing too but it's probably worth checking again with that board. At least that would narrow it down to "it's definitely the drive". Unlikely that both cards would have the same exact problem. What do you think? I am having a friend over tonight so I may only have time to check the Rev A board to see if there's any difference. I appreciate all your assistance.
  5. Thanks and here's the results of last nights test. Retesting the 1st drive for Track 00 at the edge connector: With the head all the way to the center the probe showed a HI condition. When I pressed ENTER, in XB, on the command OLD DSK1.LOAD, there was 1 pulse and it switched to LO, 3 more pulses while LO and when the head retracted all the way there was 1 pulse and it switched back to HI. Did this 3 times to be sure. One thing I didn't mention before is that when the head has retracted all the way it steps in and out the distance of about 1 track rapidly about 20 times and then there is a slight pause and then it repeats that 1 more time and stops. It's like it vibrates or chatters. Another interesting thing was the PCB of the Track 00 sensor. There are 4 wires soldered to it at its' edge that terminate in a 4 pin connector that connects that small PCB to the main PCB. I have circled it in red in the picture. Visible is the "finger" (black, straight at the back and tapered in the front), the sensor itself (black, about a 1/2" to the left of the "finger" at the end of the rails, the wires I'm talking about and the connector. With everything re-assembled and the drive connected and electrically active, but not accessing, when I touched the probe to the white wire, with the head fully retracted, it read LO. I moved it out of that position and the probe registered HI. Of the other 3 wires, 2 remained LO no matter where the head was positioned and 1 had no reading at all (still maybe a problem?). Here are the results of testing the 2nd drive (the other one that was in the PEB at the time of the spike): ============================================================== WD2793 Controller Test Pin Function Signal Type Test Result === ======== =========== =========== 15 Step Output LO - no change no pulsing 16 Direction Output LO - no change no pulsing 34 Track 00 Input *see below 35 Index Pulse Input HI - no change no pulsing ============================================================== Floppy Drive Test Pin Function Signal Type Test Result === ======== =========== =========== 8 Index Pulse Output HI - no change no pulsing 18 Direction Input HI - no change no pulsing 20 Step Input *see below 26 Track 00 Output **see below ============================================================== FYI I haven't replaced any components on the 2nd drive like I did on the 1st drive which may explain why the results are different. *Testing the 2nd drive for STEP at the edge connector and testing the WD2793 pin for TRACK 00 (These 2 different tests gave the same results): Started HI before accessing the drive. When accessing the drive it pulsed once switched to LO, 1 pulse then a fast switch to HI (more like a blink) and back to LO then another pulse and back to HI. It did this 2 times and then shut the drive down. Checked this 3 times too. **Testing the 2nd drive for Track 00 at the edge connector: Did this the same way as I did above for the drive 1 retest. Results were a bit different. It started HI then when I entered OLD DSK1.LOAD it pulsed and switched to LO and went from HI to LO 5 times with a pulse before every switch. The head does not chatter on this one.
  6. That's what I read too...255. I should probably try that again since I don't remember if it continued pulsing or not. I thought I saw it stop but maybe I should have left the probe on there a little longer. Yes, I'm only checking with the LED on and what gives me the longest time with the LED on is going into Extended Basic and typing in OLD DSK1.LOAD. XB looks for a long time before it errors out.
  7. Glad to hear that. This just got narrowed down to one thing. The track 0 sensor consists of 2 parts, the sensor itself which is "u" shaped and is located in a bracket at the end of the head travel. I believe it works like an "electric eye". The other part is a finger extending from the side of the head carriage. I think what happens is that when the head position reaches the end of its' travel to the outer edge, the finger breaks the LED sensor beam and should then set the track 0 register to LO. According to the datasheet, if this input is not received it sets a seek error. And that sounds very much like what's happening. OK, I'll have to follow the circuit traces downstream to see what other devices (ICs, caps, resistors, transistors, diodes, etc) are involved. The STEP test stopped pulsing when it reached track 0. And yes I do have another drive. 2 more in fact. One of the 2 is the brother of the drive I'm currently testing. It was in the PEB at the same time as the spike so probably has the same problem. I will do those tests again on it if you think I should. PS Love using that logic probe. Should have got one years ago.
  8. It's an Elenco 560. Has all the doodads. Does all types of logic circuits (TTL, CMOS, etc). Thought I should get a decent one and not a cheap one. BTW this is the 1st release controller card I'm testing which uses the WD2793 chip. Also, according to the WD2793 datasheet, the write protect state is not checked unless a write is performed. Anyway, here are the results: ============================================================== WD2793 Controller Test Pin Function Signal Type Test Result === ======== =========== =========== 15 Step Output LO & pulsing 16 Direction Output LO - never changed 34 Track 00 Input HI - never changed 35 Index Pulse Input Rapidly changing from HI to LO & Pulsing * Direction should be HI stepping in & LO stepping out ============================================================== Floppy Drive Test Pin Function Signal Type Test Result === ======== =========== =========== 8 Index Pulse Output Rapidly changing from HI to LO & Pulsing 18 Direction Input HI - never changed 20 Step Input HI & pulsing 26 Track 00 Output HI - never changed ============================================================== Testing of the WD2793 Controller was done by touching the pin. Testing of the Floppy Drive was done by touching the edge connector. The Step, Direction and Track 00 tests were done by moving the Read/Write head to the center(hub). From the test results, the index hole sensors appear to be working properly. What is interesting is the Step and Direction test results. They are opposite of each other. I checked that several times to be sure. And the Track 00 results should have been LO until the head reached the outer edge and then gone HI as you said. So there seems to be a problem with the Track 00 reading which I presume would affect Step and Direction. It's like the keyboard at startup. Setting it to a known state. If where the head position is is unknown then maybe the Step and Direction functions can't be performed. What do you think?
  9. Also remembered that the Gramulator has a built in cataloging routine so loading a disk manager is not necessary for diagnosing.
  10. The logic probe arrived yesterday. Here are pictures showing the index hole sensors. They are circled in red. 2 are on the motor pcb and 2 are topside. The 2 that are topside are 3 legged and the 2 on the motor pcb are 2 legged. The one topside one is located in the black "L" shaped housing and is just barely visible thru the slit. All 4 are diodes. Obviously 2 are emitters and 2 are receivers. The ones that are on the motor pcb almost look like the super diodes you see in flashlights. They are a small yellow square. I'm assuming these are the emitters and the topside ones are receivers. Any comments appreciated since I'm not sure how to test these with the logic probe.
  11. Yep. All good on all 34 lines.
  12. No. I'll download it but how do I get it into the console for execution. I have a Gramulator but would still need to move it from disk to get it into the Gramulator. Unless you know another way that doesn't require a disk drive?
  13. Yes. I found that a few days ago when searching for additional info. I was specifically looking at the TEAC FD55F drive compatibility since there is someone selling them. But they need a mod to double step. The link someone here provided unfortunately is broken so I'm hoping I can find a good link that will show how to do the mod. This is a fallback option right now. I'd like to get the Fujitsu's working again if possible. Also, sometimes a disk made in one floppy drive cannot be read in another from a different manufacturer. I've run into this same problem with CD's on my PC occasionally which is why it's a bit better to read it in the drive that created it.
  14. I sorta guessed that's what you thought. I did originally have the TI disk controller and Disk Manager 2 with 3 of the old Shugart 90K full height drives but when CorComp came out with their controller card I sold the original disk system setup in Micropendium. I suppose I could try eBay and see if someone has a Disk Manager 2 cart for sale.
  15. OK. but I still think there will be a problem. The CC Disk Manager is on a 5.25 floppy and the 5.25 floppy drives are the ones that aren't working. I have no way to transfer the program from 5.25 to 3.5. Don't know what good putting a blank 3.5 floppy in the 3.5 drive will do. With nothing on the disk the drive still isn't going to "seek". Is this wrong too?
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