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P400 Phono Board Help

Derek G

Derek G

Active Member
Hello,

I recently got my 2240 up and running after replacing a dead transformer. I rebuilt the p800 power board. New Caps. New Relay. Installed new main filter caps. Everything checked out. Set board to 35v. Moving on to the P400 phono board. Installed new new caps and transistors per recommendations of values and parts. I have very little volume. Unit makes a rather large pop when powering down in phono. FM stereo output in normal, sounds great. Have a bridged a solder? Please advise me what to check. See pic. Really hoping its something simple.... Thanks in advance. Any questions please ask...
 

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The axial cap thats vertical went from 35v 100uf to 50v 220uf. That wouldn't cause an issue would it? The large Poly caps I used are 400v 1uf. Transistors are all KSC1845s. Otherwise, other caps are close to the same values. I pretty much copied this rebuild .

Phono P400
Again, we've seen this topography on many of the Marantz receivers, their are a few components to notate, such as the failure and noise prone 2SC458 BJT's, which are replaced with Hfe matched 1845 transistors. Also updated is the glass pack diode and H409 to two 4148 diodes in series as you can see from the photo. Electrolytics were replaced with Elna Silmic II audio grades and a axial Nichicon TVX 220 microfarad capacitor along with quality ECW polypropylene at C414/415.

Sound is crisp and clear. Just running at like 1/4 volume. Yikes......
 
Just brain storming. Ive looked closely at my soldering. Everything looks legit. Side note. When I originally replaced the transformer and p800 power board I never checked the phono at higher volume. I only briefly checked all outputs at low level volumes. So. Not sure this has anything to do with me updating the p400 board afterwards. I have a feeling this has to do with the P400 receiving the proper voltage to begin with? I don't know. I need help. Thank you in advance Audiokarma guru's...:)
 
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