MA-5100 Serial Numbers Starting With AA

[BeCool]

I have an MA-5100 with serial number AA1542. I finally found something that even mentions serial numbers starting with AA, and it looks like the serial numbers are as follows: 10H01 - 99H99 & AA1001 - AA1561

Is anyone aware of any significance with the changeover to AA? And is the service manual for "Starting with serial no. 21H00" accurate for those serials?

A main reason I'm concerned enough to ask is that the schematic in both the "10H01 through 20H99" and "starting w/ 21H00" manual Show polarized capacitors C19 and C20 in a different configuration than what the actual amplifier had in it. It seems like it's most likely a misprint in the schematics judging by the circuit, but it's weird that both manuals I was able to find had the "mistake". In the actual unit, C20 has the anode on the opposite side.


Thanks in advance for any input!

--Jonathan

 

[strandtentje]

I had a look at the schematic and what C21 and C22 should connect to in there, and I'm pretty confident this PCB layout is a bit of a misprint. + of C20 should be connected to R32/34/36, not R38/Q12. Good eye for detail though, never noticed that when getting my MA5100 ready.

As to what the AA-prefix means and in what range of serial no's it belongs - no clue. Would be eager to learn though.

 

[clinic-audio]

Hello Jonathan

You are right there is a mistake on the drawing
+ should be connected with R36 like the other channel (R35)
See confirmation on the schematic !

 

[BeCool]

Thanks all! I'm embarrassed to say that I didn't think to check the actual schematics before posting here.

Looking forward to finally having this thing back in my system, maybe even this year sometime