Ah gotcha. I checked out their page on ebay and it will be an extra 40 dollars in import fees/shipping fees to get them over here in Canada so I would rather just order from Digikey
Help with Marantz 4400 scope
- Thread starter Mecrookie
- Start date
FP03 and FP04 are both nominal as tested through continuity.
H801 (anode)= -595V
H802 (cathode)= 224V
H803 (cathode)= 220V
R801 (output side)= -14.5V
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H809 appears to be bad testing it through the multimeter as well.
dr*audio
Fish fingers and custard!
R801 should have 200V on it! Check C809.
C809 is reading 21 microF on my multi-function tester. It looks fine.
dr*audio
Fish fingers and custard!
Check the resistance to ground at that point. Something is loading it down.
I am still quite new at doing these measurements. The board is out of the unit and these measurements were taken using pin 3 of J813 as ground, as I believe it is. Please correct me if this is wrong.
- terminal of C809= 1 Ohm
+ terminal of C809 = Null
- terminal of C812 = 1.3 Ohms
+ terminal of C812 = 6.8 Mega Ohms
R801 = 16.8 Mega ohms
dr*audio
Fish fingers and custard!
Bingo! R801 should be 2.2K!
You also mention H809 seemed to be bad. How did you test it? Did you remove it before you measured C812?
I have a question about resistance. Should R801 have 2.2k resistance from it to ground or from it through itself? I tested it using the 3rd pin of J813 as ground and having the other multimeter connection go through the actual resistor. Should I just put both multimeter connections on either side of the resistor? Still trying to figure things out.
For H809 I believe I took it out and tested it but I put it back before I measured C812. I will have to see tomorrow.
dr*audio
Fish fingers and custard!
Measure across the resistor only.
Ok then sorry about that R801 when tested properly has a reading of about 1.5k Ohms
Is there any thing else I can try?
dr*audio
Fish fingers and custard!
I'll have a look at the schematic.
dr*audio
Fish fingers and custard!
Please check the voltage on the output side of R801 again. Maybe you measured on the wrong point.
If you still get -14V, check the voltages on both sides of C901 and C902.
I really think you mismeasured because if R801 was really dropping 214V across it, that would be 20 Watts across it and it would be smoking.
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Hey there again. Sorry I didnt gdt back to this project for a while. I just retested that point and sure enough I tested an incorrect resistor. I am getting 200 v through it as normal. Is there any other points to test?