Recent content by ton4eff

Sorry, I didn't understand what is the problem with the "ground loop" in this case, maybe I didn't explain the discrepancy on the schematic properly... On the original schematic is obviously missing the connection between the two parts of the common ground - this connection is present on the...

I was making a clean copy of the 2325's P700 schematic (attached PDF for downloading) and I noticed that there is no connection wire between these two parts of the GND in the original schematic: So I added one: Also noticed, that for this part of the P700 PCB, there will be no GND connection...

A year later, I made a revision of this PCB, to fit currently available transistors H706, H707 - KSA1381, KSC3503. Here is the picture with animated before/after view:

As I promised, a good quality schematic for 2275 P800 is attached in PDF format.

A fellow AK'er was kind enough to send me a high quality scan of his stripped P800 PCB, which is the best option to copying it in the right manner. The distance between the holes for the H804 heatsink appeared to be of by 0.5mm, which I corrected accordingly. (In opposite to some people think...

@Steven Tate You are a 100% right! They decided to go with the lower current relay for the latest versions. Most probably for cutting the costs down... :confused: Just made a small change in the PCB design - added an option for higher current support with this one layer design on the relay...

The original 5A MY2-02 relays still hold strong for 50 years... I just thought that optional LY2-0 with double the current is a good idea, as you can see the footprints of these relays are close enough - no need to change the original design significantly. Which I prefer to keep as close as...

I decided to recreate this PCB. Most probably they use this one in other Marantz models, that I'm not aware of... In the first place, I made a clean copy of the schematic (with the vintage look preserved, of course ;)): Then, when I was working with the PCB, decided to add an option for...

There is no trick here. :) I just copy by drawing the copper traces in vector editor Inkscape (free, one can use any other vector editor...), then exporting to KiCad (free) pcb editor in order to plot the gerber files required by the pcb manufacturer... Sometimes guessing the exact dimensions...

And here is how the real PCB's came out:

Thanks for the tip Tom. There is plenty of space to add additional hole on the PCB to fit CEN-*** transistors, but in this case one should drill a matching hole in the heat sink too. At the end I decided to leave it as it is, drilling a hole in the transistor should be easier... Or installing...

Added some extra off-center holes for the smaller transistors. It indeed should be easier for installing a different footprint type transistors. Or more confusing for somebody ho doesn't pay enough attention... :naughty:

Decided to add some extra holes to fit Bourns 3386X pots. Strangely enough, it appears that the original ones are with the center pin that's not in the... center... :cool:

Thank you @Skywatcher, you're correct, I'm asking, because according to the scans I have, It's 7.4mm :dunno: The connector should fit anyway, but decided to ask just in case...

OK, the screw holes are finished, also the silkscreen and the rest of the holes. The only doubt I have is about the distance between OUT and B- pins on J710. It's exactly 5mm between the B- GND and B+...