TASCAM 38 serial number differences

[LivingRoomSounds]

Hi!
Does anybody know what differences there are between Tascam 38 machines with SN up to 400 000 and machines with SN 400 000 and higher?
I know that the SN below 400 000 machines have PCB cards that end on -01.
The SN 400 000 and higher machines have PCB cards that end on -02.
I just put -01 cards in my -02 machine. There's playback, but no record/erase.
No dc reading on the testpoints.
The only info I got is that there's differences, but does anybody know what kind of differences? Or if there's an easy way to make them compatible?
Thanks
Roman

[wkrbee]

The original 38 would would let you hear tape with the track arming button down,then it would switch to source when you punched in and back to tape when you punched out. The they made them for awhile with hearing source with the track armed in the stop mode.The too many people bitched about that and a mod was done to make the new ones act like the old ones.All three decks-32,34-38 used the same cards.

[LivingRoomSounds]

Exactly. I have an older and a newer unit and had always been wondering why there are the tape/input signal differences when arming a track.
They use the same cards, but the layout is different. You would need to modify them to make them work.
The first thing I look at on a Tascam 38 nowadays is the s/n.
I had to learn the hard way. Some "repair" shop put a newer output select pcb in my older machine. It worked for playback, but caused weird stuff happening in sync and rec mode. The schematics I found are for the older units. As far as I know there's no documentation on the newer units.
I hope I'm wrong...

[Magnetic Services]

I just checked and it looks like I have the original, #350035 42 (?)

I need a new power supply PCB; if I find one online does it matter if it's from a newer machine?

PS does anyone have tips on switching out the power supply PCB? It's nestled waaaay in there with screws in tricky places and multiple wires would need to be desoldered I really want to get this machine sounding better but it's such a headache.