Does anybody have a complete schematic for the Boss HM-2?
I have the simplified one already and am looking for the factory schematic (or a good drawing) that includes the switching.
Thanks! :D
I don't have a "factory" service manual.
just the schemo with no switching.
U can try the "factory"---Roland US in SmogTownUSA=LA.
afn
tone
Hi...
I don't have its factory schematic too.
But I have pics of HM-2's PCB.
It shows 9*TO-92 package.
This schemo shows only 3.
http://www.mif.pg.gda.pl/homepages/tom/files/hm-2.gif
BOSS usually use 4 = 2*JFET + 2*Tr for ON&OFF switching.
SPDT-switching is made by them.
3 + 4 = 7...
plus, there must always be output buffer amp.
7 + 1 = 8
last 1 is...?
This is only my guess.:)
http://www.mif.pg.gda.pl/homepages/tom/files/DS-2.gif
JFET added like this... by Q21, against bleeding(lump?) of fx-line.
DPDT-swtiching is performed now.
In the high-gain DIST/OD, BOSS is mostly done so.
BD-2, OD-3...etc.
Thanks eaze! 8) 8) 8)
Hi,Peter :)
By using Google image search,
I found another schematic drawn uniquely.
http://heavypage.narod.ru/shem.htm
This also lacks flip-flop & jfet switches again.
However output buffer stage is contained. that's a typical BOSS-style.
If you omit J1 and input into C2 - Q2 directly,
Input impedance is lowered... like the input stage of BMPI.
According to input stage, the overtone will change so much.
It may be said output stage[Q1] is also omitted.:roll:
Thank you again eaze! 8) :D
Domo arigatou! :o