Boss TR2 repair question

Started by BDuguay, June 15, 2017, 04:54:03 PM

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BDuguay

My friends TR2 had a fried 1N400x diode which I replaced but it's still not working. Upon further investigation I discovered Q9 was toast so I replaced that. Still nothing. There's D11 that has me wondering but I can't seem to find any info. This is a later Made in Taiwan version and none of the schematics I've found match up. Any help is, as always, greatly appreciated.
B.

BDuguay


BDuguay

With my jewellers magnifying tool I was able to make out markings on this D11. Also, I have another TR2 of the same design to use for comparison. The diode is a glass type coloured orange with a blue stripe and it's either A62 or 26A. Some searching suggested it might be a 6.2v zener which I have and installed but with the effect engaged it's lower in volume and distorting. Also, the working TR-2 measures 8 volts at D11 where as the troubled one measuring 6.2v.
Does anyone know what this diode is?
B.

Kipper4

Ma throats as dry as an overcooked kipper.


Smoke me a Kipper. I'll be back for breakfast.

Grey Paper.
http://www.aronnelson.com/DIYFiles/up/

BDuguay

The pedal works but for the low, distorted output. I really think the solution is getting the right diode but it doesn't help that there isn't a scheme available for this version.

Fender3D

When I got to repair schematicless stuff, I usually trace down (Reverse Enginering?) and draw a reference schematic...
This will suggest what dead parts are for...
I'd guess you're messing with a standard silicon diode there... try 1N4148
"NOT FLAMMABLE" is not a challenge

BDuguay

I'm inclined to think the same thing. I'll try and report back. It can't hurt anything right?

Fender3D

Since your working TR2 has higher voltage, I think it won't break anything, since it's not a protection diode (then not a zener).
Should it be a GE diode or Shottky, pedal will work bad(ly), but it won't suffer....
"NOT FLAMMABLE" is not a challenge

BDuguay

The 1N4148 resulted in a harsh sound both in bypass and when engaged. The 6.2 v zener worked fine in bypass. If only I knew what this mysterious diode is....
B.

BDuguay

I put in a 5.6v zener just for experimental purposes and it seems to work now even though it has different voltage readings from the know working TR-2. I've messaged Boss US and asked what the diode is. I doubt I'm going to get an answer though....
B.

Fender3D

[billy cristal voice]And the diode goes to....[/billy cristal voice]
?

sketch a diagram please, Brian
I can't stand mystery diodes...  :icon_mrgreen:
"NOT FLAMMABLE" is not a challenge

BDuguay

This just in from Boss:
Hi Brian,
It looks like it is a HZS982.

Best regards,
Roland Service Department

So I google that and get nothing diode related. Knowing there is an "A", a "9" and a "2" marked on the diode, I substituted the 8 with an A and found this:
http://pdf.datasheetcatalog.com/datasheet2/1/03752iquz6rh7le1jhodekw2ylky.pdf
B.

BDuguay

This just in from Boss:
Hi Brian,
You are correct - HZS9A2.

Best regards,
Roland Service Department

So, it's a 5 volt zener? I'm not sure how to read that data sheet.
B.

duck_arse

"type" HZS9, "grade" A2 shows as minV 7V9 and maxV 8V3. I think 8V2 is a standard value.
You hold the small basket while I strain the gnat.

BDuguay

That's what I thought because 8.2vdc is the reading I get from the known working Tremolo.
B.