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Post by 24century on Jan 4, 2015 12:11:18 GMT -5
It reads Pin 1-2 15.02 Pin 2-3 0.22 when bypassing the standup board (power directly to the main transformer)
1-2 0.31
2-3 0.22
is the result without bypassing the standup board
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Post by mastertech on Jan 4, 2015 16:40:54 GMT -5
Looks like you do not have the +15v supply. You will have to check the regulator. Your pin 1-2 should of been -15v, Is that what it was?
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Post by 24century on Jan 27, 2015 15:16:16 GMT -5
R903 open cause of losing power therefore replace it solved all the problem, it is the same case as article www.curtpalme.com/forum/viewtopic.php?t=32782. those two resistors reacting as fusible resistor, when play loud PCM signal and long time it went open. it is not an uncommon thing per Marantz design on power however disassemble the board is a real challenge. My experience is you will have to have the schematic diagram (be able to read it) and parts ready to quickly find out the problem if you don't want table of screws laying around. previous article has good detail, do enough reading prior to do the work will shortcut the process, disassembly part you are on your own |
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Post by mastertech on Jan 29, 2015 10:18:26 GMT -5
Glad to hear you got it all straightened out.
Am I the only one on the net giving this kind of help. It seems everywhere I am assisting, someone is always linking to my posts in another thread in another forum. Kinda funny, really.
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Post by 24century on Jan 30, 2015 11:01:26 GMT -5
Because we are technical I guess, like me I am not good on marketing and don't have a desire to.
Have another case if it gets your interest:
Have a Bose Acoustimass 9 system which is an analog based old school, it do 2 channel in and dsp to 5.1, didn't use it for quiet a while wanting to convert the base module to a powered woofer for the Marantz. The base module has a tube type of design and make it sound real good.
It is not that easy per Bose design, they make it fairly hard for any modification, did it myself on power part that tested OK but there is a mute thing keep the sound output that has to be bypassed.
I do have the schematic diagram drawing and "THEORY OF OPERATION" book can email and provide necessary info, let me know if you are interested, thx
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Post by mastertech on Jan 30, 2015 16:06:46 GMT -5
Email it to me and let me have a look. I am sure you have my email, LOL.
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Post by 24century on Mar 19, 2018 19:51:53 GMT -5
My Marantz has been working great and as time passed, I am getting familiar with almost all features and get it on the best performance, I like the sound.
But people will never be satisfied with the sound and I am one of them.
Goal of MOD: increase the output watts on stereo, front left & front right by replacing with more powerful Darlington transistors (pair, one PNP & one NPN), also looking for upgrade the op-AMP meantime.
By getting into the schematic again, that will be Q521 & Q519 FL, Q619 & Q621 FR by the end AMP and model #s are STD03P & STD03N
Op-Amp will be straight by replacing them to Hi-Fi class from NJM to TI OPA2604.
Question I have is looking for recommendation for the type of Darlington transistors to be replacing with
current design make it as 90w/channel, looking for upgrade to 120-150w, thx
Question I have
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ocir
New Member
Posts: 2
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Post by ocir on Jul 12, 2021 9:34:19 GMT -5
I would like to join this topic. I know this is an older topic, but my problem is exactly the same that's why I'm continuing this. If this is not desired, please let me know and I will create a new topic.
My problem is exactly the same as the topic starter. Red light continues to flash rapidly and the SR7002 cannot be turned on.
However, I do have +15V and -15V measured on the REG PWB A board when I hold down "PURE DIRECT", "7.1CH INPUT" & "CLEAR".
So the R903 and R904 are not the problem here. Any idea where I should look further? Because most solutions come with a faulty R903.
Thanks in advance.
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ocir
New Member
Posts: 2
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Post by ocir on Jul 15, 2021 11:20:17 GMT -5
Okay, just measured again. The +15V fluctuated too much for my liking. Especially when switching on the relay.
Yet again R903 and R904 measured properly. So it turned out that there was indeed an error.
R903 now had a resistance value of 2K1 instead of 0.33R. R904 was 0.5R
This is most likely the culprit.
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