Stuff found on my hard disk.
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Boss Tone Info and Chrononology
Rob S, 2021/02/21
I've kept the common circuit numbering (1 to 5) from the web, but there's a bit more to it.
Also there's a difference between manufacturing build and the schematics alone.
All models are au-0606 until we get to the 6248 Sho-Sound
Alhambra (1967, 1968, maybe 1969)
Pasadena marked au-606 but has Nashville circuit
Features identifying versions:
- external labels
- pcb color and pcb number etched on solder-side
- transistor packages and location of transistor on boards.
- The California circuit puts the transistors on opposite corners of the PCB.
and the Nashville put the transistors in the same corner.
- parts marked ***
Revision History:
- added info on Pasadena unit
- added info on PCB markings
- resolved some of the transistor markings
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California 1 schematic V1.0
C2 should be 220p
The transistors have dots which indicate the hFE's; see details below.
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Circuit 1
Schematic: California 1
Label: Alhambra Calif, au-0606
PCB: IC-0193 B ; solder-side marking
PCB has a large square pad between the PCB number and mounting hole.
*** Diodes orientated across PCB;
Transistors:
2x2N3397 NPN, Package TO-98 skirt, orange dots
Orange dots => hFE=135, based on same process 2N2926
TO-98 is like a TO-92 with a round skirt at the bottom
Knobs: two different markings.
Circuit 2
Same design as Circuit 1 except different PCB
Schematic: California 1
Label: Alhambra Calif, au-0606
PCB: Likely IC-0193 C ; solder-side marking
*** Diode orientated along PCB
*** 100k orientated along PCB
(*** 33k & 470R loaded on PCB)
Transistors:
Both NPN, TO-92 but no dots. I expect 2xMPS6513
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Circuit 3
Schematic: California 2
Label: Alhambra Calif, au-0606
PCB: IC-0193 C or D(?)
Ground hex post does not have a tinned area.
*** 100k (located near wires) mounted on an angle,
100k moved to mount Transistor in different holes,
red wire also moved.
Parts:
Links loaded in place of 33k & 470R.
Q1 feedback resistor 10MEG
Caps: 2x20n
Output cap: 20n
Feedback cap: 220p
Transistors:
Q1 2N3397 NPN, TO-98 skirt, yellow dot
Yellow dot => hFE=225, based on same process as 2N2926
Q2 Motorola MPS6513, NPN, TO-92, gold leads ; hFE = 90 to 180 @ 2mA, calc avg hFE = 135
Example: (Sir H C, 2006)
"California Bosstone, 2N3397 (yellow dot) and MMPS5513 (face down) vertical cap is 220k,
cap under other is .02 also, can not read diode values."
Note first M is the Motorola logo not the part number.
Circuit 4
Schematic: California 2 + cap mod
Same as circuit 3 except output cap is 470pF; Solar 470M Z5R.
The cap is thicker and is not stacked with the other caps in
the middle of the PCB.
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Circuit 5 Nashville circuit with both transistors next to each other.
The upper transitor is the NPN and the one nearer the corner the PNP.
This have a number of sub variants.
Pasadena
Uses the "Nashville" circuit.
Has red white blue wires
Schematic: Nashville
Circuit: Nashville
Label:
Pasadena, South Pasadena California
PCB: Text "IC-0193 F"
Brown color on component-side
Dark green soldermask on solder-side
Parts: 100n input cap (Solar brand)
Others? (Solar brand)
2x 18k's
Transistors: Q1: Motorola SPSxxxx, NPN, TO-92, gold lead
Q2: ???, PNP, TO-92, gold lead
Diodes: 1N4001?, 1A rectifiers, Black, Motorola
Not fully Identified:
Similar to previous but different transistor packages.
Schematic: Nashville
Circuit: Nashville
Label: ?
PCB: Brown color on component-side
Parts: 10n input cap
Transistors Q1: NPN, TO-106 button
Q2: PNP, TO-92
Diodes: 1N4001
Not fully identified: (from a schematic)
Schematic: Nashville
Circuit: Nashville
Label: ?
PCB: ?
Parts: caps 2x18k, 3x10n
Transistors:
Q1: F70N1 1142812 (maybe E70N1), NPN; Probably F = fairchild
Q2: M852 95232, PNP ;implying M= motorola symbol 8 = 1968, 52 = wk52, part no. = 95232
A part source indicated: NTE159 = 2N3906 = 95232
Diode: 1N4001
Comments:
I have a suspicion the Fairchild part might be a TO-106 button head.
That would essentially be the same as next version with he 2N3565.
Nashville
Schematic: Nashville
Circuit: "Nashville" Circuit
Label SHO-Sound, Nashville
PCB: No PCB number.
PCB is light green semi-trasparent fibreglass
PCB tinned but with no soldermask.
Parts: (Sir HC unit)
3x10n
18k + 18k
Transistors:
Q1: 2N3565. NPN, TO-106 button package
Q2: Motorola 924 95232, PNP, TO-92
The M at the start of M924 is a Motorola Logo not the part number.
Likely to be date 1969 and part number 95232.
\E B C/ botton view, gold leads
Diode: GI (General Instrument)
look like 1A rectifiers.
Variants:
*** Caps seem to vary: 10n, 20n, 50n
Not fully identified:
Label: SHO-Sound, Nashville
PCB: ?
Parts:
RLBJR65 (Richard Boop)
Re: Jordan Bosstone and Bossboost pictures
« Reply #9 on: August 20, 2006, 11:05:42 PM »
"Interesting! I've also seen the Sho-Sound Nashville model with
3 - .05uF, 1 - 50pF, Q1 - MPS6513 and Q2 - 2N4249, unreadable diodes, ..."
Q2: 2N4249 hFE = 100 to 300, PNP, Silicon
Comment on this:
MPS6513 NPN is a TO-92 package, and the PNP 2N4249 is a TO-106 button.
This swaps the position of the TO-92 and TO-106 compared to previous versions.
One example of a board with this build had a blue component-side PCB.
I can only assume these are later manufacturing runs.
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Transistor packages:
TO-92 common flat-face plastic package
TO-98 like a TO-92 with a round skirt at the bottom
TO-106 Small button head
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Bias points
For ckt1, calc Q1 at VC1=3.4V
For ckt3,4, calc Q1 at VC1=3.2V
For ckt1, 3, 4 calc Q2 at VC2=3.05V
For the Nashville circuit, VC1=5.3V, VE2=5.9V
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