Marantz 510m Resurection
Ok I have an old marantz 510m that needs a new left driver board and possibly some new transistors. I'm going to try to bring this baby back to life. I am new to this and it is going to be a learning experience so please be patient.
Pics of the working board that I am going to replicate.
Re: Marantz 510m Resurection
If only we could teach Google to solder...life would be different.
That's a double sided board, isn't it? You still connect the dots but on both sides. You may need to solder small wires across to connect the bottom to the top pads in some cases. The original was plated through. That means desoldering may take longer.
Order 2X the capacitors you need and redo your other board while you are at it. You may need to use a TO-126 or similar case for the TO-5 transistors unless you can find those push on heatsinks.
Keep in mind that Marantz would match transistor compliments and pairs. Also, one stage was only one gain grouping away from the next stage. The manual would give you more detail (I don't have any more). I do have the schematic, as you do.
Those boards are small and well laid out with lots of clearance. If you created two new boards, you go to heaven and why not? If you are generating a new PCB then making two is the same cost. Components for one board vs. doing two...same thing; almost the same cost. Do it all, do it the best you can.
So I guess I agree with Chris but on STEROIDS! ;)
Ok, How do I tell the rating of the resistors.
They are all color coded. I understand that much, but do the bigger ones have different specs? Also some resistors are different colors.
This is a grey resistor, I can't tell if the tolerence is the green band or the red band.
okay reading the schematic helps. I figured out the wattage for the larger resistors, however, i am still questioning the pictured ones.
When I am buying replacement resistors does their composition matter... as long as the rattings all match up?
On a recent rebuild I substituted 1% metal film for all of the resistors. If I was rebuilding your 510 I'd be inclined to use some "boutique" resistors that go down to .1% tolerance. This may change the cost from pennies a piece to 50 cents or more per resistor. Using silver mica caps is nice and you can purchase low ESR electrolytic caps too.
Reading the schematic should tell you most of what you need to know about the component values. If you do not have a parts placement layout diagram or if the PCB does not have component designations silk screened on it, then you need to study the PCB a little more. You should be able to figure it out.
As Chris mentioned earlier, the board looks double sided. That makes DIY PCBs a little trickier. If you are cloning the boards it may be very difficult with limited experience.
I compiled a list of the 63 resistors i will need. The unmarked ones are 1/4 watt +/- 5% tolerance
Ohms Watts Comments
1) 20k 1/2w
2) 51 1/2w
3) 10 1/2w
4) 10 1/2w
5) 8.2k 1/2w
6) 24k 1/2w
7) 8.2k 1/2w
8) 10k 1/2w 1% tol.
9) 2.7 1w cc
10) 24 1w
11) 2.7 1w cc
12) 250 2w
13) 250 2w
14) 4.3k 2w
15) 4.3k 2w
16) 750 3w
17) 730 3w
18) 1k 4w
19) 1k 4w
20) 1 5w ww
21) 0.3 7w
22) 0.3 7w
23) 0.3 7w
24) 0.3 7w
38) 500 bias adjust
41) 510 2% tol.
51) 20k output offset adjust
Now I just have figure out the proper capacitors, diodes and transistors. And figure out where to order from.
I tested the output transistors and one of them seems to be shorted. I think this is what caused the failure in the first place. However I'm not sure where i can find a replacement for that particular transistor. I can't seen to find them online.
Also, what would be the benifit of installing new power capacitors as you guys suggested?
Whoa! Hold on and take a breath.
I would replace most of the resistors with metal oxide, not metal film. If you want to, you can install metal film in the input signal path. Upgrade the capacitor types (ie: avoid ceramic types).
Once you have it running, replace the filter caps. They are over 30 years old now.
Time to take your time and recheck a few things. Also, making more than one board now seems to make a lot of sense. If you can create a board layout and generate gerber files they can be professionally made.
For outputs, you will need to replace all 8. Use something like MJ21195 / MJ21196 or MJ15024 / MJ15025. Match them best you can. Consider too, the 2500 receiver used a very similar output heatsink assembly but was a newer design. You could clone that and stick it in.
Okay I have made a list of all the components that I will need to replicate the board.
Chris, Is the only reason you recomended metal oxide resistors instead of metal film because they are cheaper. Because, I thought metal film generated the least amount of noise... excluding Wire Wound.
Also for making the PCB's is the "Iron on laser printer" method any good. And in your experience what is the best program for designing the board.
Sorry about all the questions, but I am new to this and want to make sure I don't screw it up.
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