PROTRACK 20B (KJ3) STORE PROBLEM

[TRADMARK-X]

Greetings from England!

I am new here, so hope you don't mind me asking a few technical questions that someone may be able to help me with?

A bit of a background:-
I used to work for a local circuit board manufacturing company whereby we had a faulty ProTrack which I was allowed to take home to repair & use, I think at the time I replaced a DC-DC converter. It was very useful for finding problems in some of the vintage studio & broadcast audio equipment like master tape recorders that I restore in my spare time. On leaving the company I was hoping they would forget about the ProTrack so it could be 'liberated', but sadly they wanted it back....

Anyways, I was a bit lost without it but can never afford a working unit & spotted one of these Ex-Navy 'KJ3' units that I thought would do the job as I will only ever use it stand alone really.

The fault I have is that it works okay until I try to save something like changing the LCD contrast etc. whereupon it will just lock up & destroy the firmware on the Flash - it then has to be re-flashed in my programmer.
If I bend my Pin 1 (VPP) up on the Flash, & earth it to pin 16 with a bit of wire, it then goes through the motions of writing without knackering the firmware, but obviously doesn't save anything.

I have found a really odd fault, not sure if it's 'the' fault; but when saving there is a relay to provide 12V to pin 1 when writing. I'm not sure if it's right as when writing this relay does bursts of about 85ms on & 10ms off, the bursts are about 3sec on & 1sec off – is it supposed to do this?

Then there is a physics bending thing going on..... This relay contacts stick together after a few bursts for no reason I can think of! The only 'load' after the contacts is a 0.1uf cap. & a 10K resistor to ground. I have tried 6 relays now of different makes & forms & they all do it. A thwack with a screwdriver handle releases the contacts – the relays should be good for 1ms going by the data, so completely clueless on what's going on here....

Can anyone suggest anything as to why the relay is doing this & if it's supposed to pulse during a save please?

Cheers,
              Mark...


 

[jvthorsley]

Hi Trademark-X
You would be far better off with the KJ2 version.
Plus Tech Support (Curtis) may even let you have circuit diagram for this older version.
I have written about this on this Forum.

[fetron]

Dear TRADEMARK-X!

Paula wrote about a similar error. It can be read below.
https://huntron.com/forum/index.php?topic=326.msg1504#msg1504

Paula resoldered the U3 ic and U4 ic pins and the flash save works fine.

Have a nice day!

[TRADMARK-X]

Hi Fetron,

I have spoken to Paula a few days ago & the fault is not resolved.
I found we were both using P28F001BX-T120 instead of P28F001-B120 as stated in the BOM.
I believe one boots from high ram & the other low - we are not sure if this will make any difference but have both ordered the correct 'B' versions & are just waiting for them - though can't see if it makes any difference...
I am trying to find out what supposed to happen on pin 1 during a save, as I mentioned mine pulses & then the relay goes short for no reason I can think of. I'm trying to find out if anyone else can listen for a pulsing relay sound when saving - it will be very quiet as is reed relay, but I can hear it with the lid off.

Cheers,
Mark...

[TRADMARK-X]

Hi Jvthorsley,

Well I have the KJ3 now so have to persue it, it is usable just I can't save any changes nor calibrate it.

Cheers,
Mark...

[fetron]

Okay.

Try Catalyst flash ic CAT28F001Pi-12B, or CAT28F001PB-12B, or CAT28F001PA-12B.

Keep ya head up.

[admin]

Hi Mark,
I did chat with our programmer about this relay circuit but we didn't come up with anything that would be helpful. The engineer who originally designed it moved on a long time ago. When the relay is "stuck" do you still see any power being applied to the activator pins? Maybe there is some noise here or an issue with the Q1 FET or the D66 diode?

[TRADMARK-X]

Hi Fetron,

'B' version Flash (boots from lower RAM) turned up yesterday, programmed it under 'B' type, popped it in & all is good – I ran the calibration & when plugged into the computer running diagnostics it passed everything! Ace!

Appears; A P28F001BX-Txxx WILL NOT WORK IN THE PROTRACK!

I would still like to fix this weird U42 relay sticking issue on the VPP line to pin 1 of the Flash & am starting to wonder if this has happened on all ProTracks, maybe due to the pulse frequency that the reed relays don't like?
It's certainly weird – not seen anything like it before, it's just got 12V on one end of the contact & the other is through a 10K resistor & 0.1uF capacitor to ground, yet it keeps sticking on!

I have even strapped a 0.1uF cap across the contact in case some RF on the line was causing it, no difference.

I presume this relay is to protect the integrity of the flash when not saving due to surge or power fail etc....

Cheers,

Mark....
 

[TRADMARK-X]

Hi Admin,

No, the coil is not energised & continuity can be seen between Flash Pin 1 & 12V rail after power off.
I have to give the relay a thwack to open the contacts again. I just bought 2 Coto relays for £30 - they do the same.... I put a 0.1uF cap across the contacts in case of RF presence but no change.

I may try to set the AWG up to simulate the timings that the ProTrack is hitting the relay with to see if the relays stick outside the instrument. Something funny going on here....

Cheers,
Mark...

[admin]

You could try testing the relays externally using the ProTrack Pulse Generator in pulse mode. Maybe it will provide additional insight.The pulse frequency will match the ProTrack frequency.

[TRADMARK-X]

Good idea - I will give it a try, saves setting up the AWG - Cheers!

[TRADMARK-X]

Hi Admin (Curtis?),

I tried the relay on the ProTrack & was surprised & what frequency it would switch up to - couldn't get it to stick though, nor on the AWG.
I am then again suspecting noise on the 12v rail, but upon checking it doesn't look to bad with maybe 100-200mV of noise riding on top of the DC. The noise looks pretty random, though if I use chassis for scope earth I have a 121Khz pulse of about a volt. I have checked the capacitors on the 12V rail & they look okay & even added some temporarily to see if any change, but just the same really!
I've now got sick of this weird fault now & have decided that the 'fix / bodge' will be to replace the reed relay with a Solid State Relay - looking at putting an Omron G3VM-61 in, should do the trick with nothing to stick!

Everything is otherwise working okay & passes everything in Workstation diagnostics.

Cheers,
Mark...

[Al1234]

  lol, finally someone figured it out on their own. information is gold until its shared. once shared over time gold turns into xxxx.
https://www.youtube.com/watch?v=VMnjF1O4eH0

[TRADMARK-X]

Can anyone with a ProTrack please confirm if they can hear the relay pulse during a save?
You should be able to hear it without opening it - just listen closely to it when saving....
I am trying to establish if it should be doing this or should just close at beginning of save & open again at the end.
Mine pulses, well for a bit anyway until the relay sticks again....

Cheers,
Mark...
[TRADEMARKX@NTLWORLD.COM]

[admin]

lol, finally someone figured it out on their own. information is gold until its shared. once shared over time gold turns into xxxx.
https://www.youtube.com/watch?v=VMnjF1O4eH0

This is relevant how?