Triaxis Optocouplers, LDRs, Relays

[wartime-novelty]

I made a little progress with this.

Replaced LDR 21 and now the tonestack functions and i have been able to set it to 33k.

However going through the other steps I am struggling with the treble Bass and gain

It seems that when measuring for treble low on the outside legs of LDR 27 & 28 I get no reading but going onto treble high I get a reading but the trimpot for treble low adjusts it but the treble high one doesn't.

Do you happen to have the original document? I'm thinking maybe the instructions I have are messed up.

Thanks again
Tony

 

[Synrgy77]

Do you happen to have the original document? I'm thinking maybe the instructions I have are messed up

I only have the pdf found on the internet.

It seems that when measuring for treble low on the outside legs of LDR 27 & 28 I get no reading but going onto treble high I get a reading but the trimpot for treble low adjusts it but the treble high one doesn't.

I think a part of your issue may come from the TX1 LDR diagram of this thread. Look at the printscreen Ive got from a YouTube video (LDR surrounded by red circles) . We can see that LDR27/28 are not at the same place.

http://imgur.com/a/ManV1c1

 

[wartime-novelty]

Hi that link doesn't work.

Thanks for getting back to me.

Starting to think I should maybe lift the ldrs and see what's what haha.

 

[Synrgy77]

that link doesn't work.

[/url]https://www.flickr.com/photos/184069038@N07/48674691976/ The original TX1 implementation c...iōn de un Mesa Boogie Triaxis" at 11min 25sec

 

[wartime-novelty]

that link doesn't work.

[/url]https://www.flickr.com/photos/184069038@N07/48674691976/ The original TX1 implementation c...e] That makes a lot more sense now! Thanks

 

[Luca80]

According to the original schematic, if correct, LDR 27 and 28 are the ones for TREBLE.
I uploaded few photos of the boards, one of them is the following:

[/url]DSC06814 by Luca Paltera, on Flickr[/img]

Of course I can change the diagram to include the correct positions if you can confirm that (my triaxis is in the flight case at the moment).

 

[Synrgy77]

Of course I can change the diagram to include the correct positions if you can confirm that

LDR24 and LDR25 are missing on screenshot

Circles:

Red: LDRs
Green: Trim pots
Yellow: Calibration switches

http://imgur.com/a/ManV1c1

 

[wartime-novelty]

According to the original schematic, if correct, LDR 27 and 28 are the ones for TREBLE.
I uploaded few photos of the boards, one of them is the following:

[/url]DSC06814 by Luca Paltera, on Flickr[/img]

Of course I can change the diagram to include the correct positions if you can confirm that (my triaxis is in the flight case at the moment).

Hi Luca.

I'm probably not going to get a chance to look at this again until late Saturday /Sunday.

But when I do I will lift the ldrs in question to fully confirm. For further info mine is a very early unit with serial number #175 from 91/92 (cant remember the exact year but it is written inside)

 

[wartime-novelty]

Just had another look while the wife goes out.

on the outside of ldr 27 & 28 i'm getting no reading at all.

Same with Low Gain (unless i switch gain to 0 but obviously that wont calibrate right)

Both just read out of limits.

Other than this i've managed to get everything set.

Tomorrow i'll pull the LDRs and see what the silkscreen says.

Thanks again to all for your help

 

[wartime-novelty]

Right i've made a little progress here.

Swapped the MC14042 for treble and was able to calibrate that & Gain High.

Gain low however is proving very tricky.

With gain set to 0 as if setting gain high i can get a solid reading and it adjusts accordingly. However with it on 10 as it should be I just get OL

However if i push down on the cable connecting tx3a and TX1 boards i get a reading but it jumps around everywhere.

I'm gonna guess this cable is failing.

Does anyone know what these connectors are called?

 

[wartime-novelty]

Right i've made a little progress here.

Swapped the MC14042 for treble and was able to calibrate that & Gain High.

Gain low however is proving very tricky.

With gain set to 0 as if setting gain high i can get a solid reading and it adjusts accordingly. However with it on 10 as it should be I just get OL

However if i push down on the cable connecting tx3a and TX1 boards i get a reading but it jumps around everywhere.

I'm gonna guess this cable is failing.

Does anyone know what these connectors are called?

edit: Actually i powered it up and everything still sounds way off. And lead 2 red has no signal now.

Edit2 : swapped IC5 and its all ok now calibrated gain. Also I can confirm that LDR 27/28 are opposite on the board on my V1 than the diagram on here.

So now to figure out why ld2 red isnt working.


Thanks again guys you have been amazing!

 

[Synrgy77]

Does anyone know what these connectors are called?

Try to clean the connectors with Deoxit. If it dosent work, change the flat ribbon cables and IDC connectors. Does your TriAxis has colored or gray ribbon cables ?

So now to figure out why ld2 red isnt working.

LD2 and Presence share IC4. Master vol. and DV share IC2. If you need to look at other digipots functions (LD2, Master vol., Pres., DV), they are located on TX2D under TX3A

http://imgur.com/gallery/MlTBv4n

 

[wartime-novelty]

Does anyone know what these connectors are called?

Try to clean the connectors with Deoxit. If it dosent work, change the flat ribbon cables and IDC connectors. Does your TriAxis has colored or gray ribbon cables ?

So now to figure out why ld2 red isnt working.

LD2 and Presence share IC4. Master vol. and DV share IC2. If you need to look at other digipots functions (LD2, Master vol., Pres., DV), they are located on TX2D under TX3A

http://imgur.com/gallery/MlTBv4n

They're coloured cables but it seems the cable is fine it was one of the ics on tx3a.

Ld2 green & yellow are working fine but red just has a really weak clean signal

 

[Luca80]

Of course I can change the diagram to include the correct positions if you can confirm that

LDR24 and LDR25 are missing on screenshot

Circles:

Red: LDRs
Green: Trim pots
Yellow: Calibration switches

http://imgur.com/a/ManV1c1

It would be great to have a copy of those schematics! The two LDR24 and 25 are further on the right side of the board, that is why you can't see them in the video. By the way I took a photo of them:

[/url]DSC06819 by Luca Paltera, on Flickr[/img]

You can see the trimmer for the dynamic voice (D.V.)

The board layout doesn't show any LDRX2A and X2B, so they must have been removed at some point, possibly starting from version 2.0.
I just uploaded a newer layout at the following link:

[/url]Main Board LDR Layout 2 by Luca Paltera, on Flickr[/img]

 

[wartime-novelty]

Of course I can change the diagram to include the correct positions if you can confirm that

LDR24 and LDR25 are missing on screenshot

Circles:

Red: LDRs
Green: Trim pots
Yellow: Calibration switches

http://imgur.com/a/ManV1c1

It would be great to have a copy of those schematics! The two LDR24 and 25 are further on the right side of the board, that is why you can't see them in the video. By the way I took a photo of them:

[/url]DSC06819 by Luca Paltera, on Flickr[/img]

You can see the trimmer for the dynamic voice (D.V.)

The board layout doesn't show any LDRX2A and X2B, so they must have been removed at some point, possibly starting from version 2.0.
I just uploaded a newer layout at the following link:

[/url]Main Board LDR Layout 2 by Luca Paltera, on Flickr[/img]

Also the bottom LDR for low gain (19?) seems to be a vtl5c4/2 on mine

 

[Synrgy77]

Here's a much more detailed view of TX4 board.

http://imgur.com/gallery/9XMp4L2

 

[Luca80]

LDR24 and LDR25 are missing on screenshot

Circles:

Red: LDRs
Green: Trim pots
Yellow: Calibration switches

http://imgur.com/a/ManV1c1

It would be great to have a copy of those schematics! The two LDR24 and 25 are further on the right side of the board, that is why you can't see them in the video. By the way I took a photo of them:

[/url]DSC06819 by Luca Paltera, on Flickr[/img]

You can see the trimmer for the dynamic voice (D.V.)

The board layout doesn't show any LDRX2A and X2B, so they must have been removed at some point, possibly starting from version 2.0.
I just uploaded a newer layout at the following link:

[/url]Main Board LDR Layout 2 by Luca Paltera, on Flickr[/img]

Also the bottom LDR for low gain (19?) seems to be a vtl5c4/2 on mine

VTL5C4/2 has a total of five legs, two on one side, three on the other, whereas VTL5C9 has four legs only. Are you able to confirm that LDR19 has five legs? My unit is in the rack and photos I took don't show them

 

[Luca80]

Here's a much more detailed view of TX4 board.

http://imgur.com/gallery/9XMp4L2

Thanks for that, TX4 is much easier to figure out, since there are no stacked LDRs.

 

[wartime-novelty]

It would be great to have a copy of those schematics! The two LDR24 and 25 are further on the right side of the board, that is why you can't see them in the video. By the way I took a photo of them:

[/url]DSC06819 by Luca Paltera, on Flickr[/img]

You can see the trimmer for the dynamic voice (D.V.)

The board layout doesn't show any LDRX2A and X2B, so they must have been removed at some point, possibly starting from version 2.0.
I just uploaded a newer layout at the following link:

[/url]Main Board LDR Layout 2 by Luca Paltera, on Flickr[/img]

Also the bottom LDR for low gain (19?) seems to be a vtl5c4/2 on mine

VTL5C4/2 has a total of five legs, two on one side, three on the other, whereas VTL5C9 has four legs only. Are you able to confirm that LDR19 has five legs? My unit is in the rack and photos I took don't show them

I will get a photo sometime during the week. I've put it all back in the rack for now.

 

[wartime-novelty]

It would be great to have a copy of those schematics! The two LDR24 and 25 are further on the right side of the board, that is why you can't see them in the video. By the way I took a photo of them:

[/url]DSC06819 by Luca Paltera, on Flickr[/img]

You can see the trimmer for the dynamic voice (D.V.)

The board layout doesn't show any LDRX2A and X2B, so they must have been removed at some point, possibly starting from version 2.0.
I just uploaded a newer layout at the following link:

[/url]Main Board LDR Layout 2 by Luca Paltera, on Flickr[/img]

Also the bottom LDR for low gain (19?) seems to be a vtl5c4/2 on mine

VTL5C4/2 has a total of five legs, two on one side, three on the other, whereas VTL5C9 has four legs only. Are you able to confirm that LDR19 has five legs? My unit is in the rack and photos I took don't show them

Here you go

https://www.dropbox.com/s/1vealvzl1cmkl1q/DSC_0051.JPG?dl=0