[Potato Cakes]

Picture of board and trafos for reference.

Are you using MPSA18s and that is reason why all of the transistors are backwards. Also, you don't have the jumper connected. This has to be installed unless you are using potentiometer for trim.

Thanks!

Paul

[Bakula]

Are you using MPSA18s and that is reason why all of the transistors are backwards. Also, you don't have the jumper connected. This has to be installed unless you are using potentiometer for trim.

Thanks!

Paul

Yep, MPSA18s I happened to have on hand already.

And I did have the jumpers connected when testing. The pictures I posted were of the 3rd of 3 boards I attached to test and I took the pictures before I put the jumper in. I edited my original post to say that but it's kind of an easily missed footnote.

I've since replaced just about everything and measured all the resistor values for accuracy and still no dice.

Thanks for taking a look.

[Whoops]

Yep, MPSA18s I happened to have on hand already.

MPSA18 are great transistors for this project

[Potato Cakes]

MPSA18 are great transistors for this project

I second MPSA18s for this circuit.

Unfortunately, this is going to come down to scouring over all of your solder pads. You may have missed one or even one of those resistors may be out of place. This sounds like it's one of those common issues that requires some annoying time double triple checking. I see you have replaced everything but you may still have a stray solder joint. It sucks but it is part of the process sometimes.

Thanks!

Paul

[-Hale]

Hey all,

Amazing project. Gearing up for my first pair of these at the moment.

I was wondering: Do any alternatives exist for the Grayhill rotary switch (71BDF30-03-1-AJN). It seems out of stock literally everywhere. Searching the forums didn't yield a lot of results.

Thanks in advance!

Hale

[scott2000]

Just in case.....


https://www.4starelectronics.com/part_search/search_results.asp?partid=71BDF30-03-1-AJN&x=21&y=8

Most likely pay dearly for them but who knows. I've never actually completed a transaction from them but have had correspondence from their sales reps and plan to hopefully grab some things from them in the future.

[-Hale]

Just in case.....

Oh, thanks! Contacted them for a quote. I'll update here when they respond.

[Whoops]

I was wondering: Do any alternatives exist for the Grayhill rotary switch (71BDF30-03-1-AJN). It seems out of stock literally everywhere. Searching the forums didn't yield a lot of results.

Did you try to contact Colin at Audiomaintenance?
I always bought that switch from him

I can see that in Mouser they are expecting to have the switch in September and in Digikey they expect it in July:

https://pt.mouser.com/ProductDetail/Grayhill/71BDF30-03PAJN?qs=ls7QRyWmRk5mxfL8CLHOfg%3D%3D

https://www.digikey.com.au/product-detail/en/grayhill-inc/71BDF30-03-1-AJN/71BDF30-03-1-AJN-ND/530760



You could use another switch for sure, but then you would have to solder individual wires from the switch to the right places on the pcb, it's not a nice task.
I think it's better to wait for the correct one so it fits perfectly on this PCB.

It seems more people had problems getting this switch last year, maybe some shortage of stock due to Covid, I dont know:


https://groupdiy.com/index.php?topic=74867.0

[digrecording]

I think this guy might have some.

https://www.ebay.com/itm/Grayhill-71BF30-03-1-12N-3Decks-1Pole-Deck-12-Position-30-PCB-Rotary-Switch-/203307521320

I ran into the same problem of not being able to find the switch anywhere. Of course I'm not %100 positive that these are a match but I'm confident enough that I bought myself 2 for the 2 kits I'm building.

Hope this helps

[-Hale]

I think this guy might have some.
https://www.ebay.com/itm/Grayhill-71BF30-03-1-12N-3Decks-1Pole-Deck-12-Position-30-PCB-Rotary-Switch-/203307521320
I ran into the same problem of not being able to find the switch anywhere. Of course I'm not %100 positive that these are a match but I'm confident enough that I bought myself 2 for the 2 kits I'm building.

Thanks for the link! I'm not sure if these are compatible. According to the spec sheets, the difference between these (71BF30-03-1-12N-F) and the 71BDF30-03-1-AJN is that the AJN has Adjustable index stops whereas the ones you linked have fixed index stops.

Is there someone more knowledgeable on the subject who could chime in wether this is a problem or not?

Did you try to contact Colin at Audiomaintenance?
I always bought that switch from him
I can see that in Mouser-....

I didn't see them in stock on AML, so I just assumed it was a no go. But I'll try contacting him for sure.

Thanks for the help so far everyone, appreciate it.

[Whoops]

I didn't see them in stock on AML, so I just assumed it was a no go. But I'll try contacting him for sure.

Thanks for the help so far everyone, appreciate it.

Yes try to contact Colin, because he is probably waiting for those parts and maybe he can put you on a waiting  list

[digrecording]

I believe in this case the stop pin only prevents the knob from turning beyond 360 degrees. The schematic utilizes all 12 steps so it's not like you need to limit the steps. The seller also states that he's guessing because there is no marking. When I searched the model number he gave it turned up a Greyhill that had the contacts all around the outside so I'm not sure he's correctly identified it. In any case there are 2 headed my way. I will let ya know if they'll work once I have one in hand.

[-Hale]

I believe in this case the stop pin only prevents the knob from turning beyond 360 degrees. The schematic utilizes all 12 steps so it's not like you need to limit the steps-...

Ah, I see.

That would be great, thanks!

[digrecording]

I got the switches in today and they sure seem right. The stop point is fixed but it's fixed in the right place.  He's selling as new old stock and they fit that description. There was a little bit of tarnish on the pins but clearly hadn't been soldered. Some flitz polish cleared that right up. I don't have my kits assembled enough for audio test but my continuity test looked A-ok. I'm confident they will work.

Cheers - M

[innercityman]

Hi guys,

are these EZ1290 pcbs still available for sell ? I f yes, can you give a link please ?

[boomfred]

You can by some here :
https://analogclassics.com/product/ez1290-pcb/

But you will have to pay custom fees.

[digrecording]

Feast of carnhill pleasures.

Audio maintenance order came in today. Let the soldering bagin!

The set with that Marinair's on the right are for the EZ1290's

[-Hale]

I got the switches in today and they sure seem right. The stop point is fixed but it's fixed in the right place.  He's selling as new old stock and they fit that description. There was a little bit of tarnish on the pins but clearly hadn't been soldered. Some flitz polish cleared that right up. I don't have my kits assembled enough for audio test but my continuity test looked A-ok. I'm confident they will work.

Cheers - M

Great news, thanks for the heads up!

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