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Loudness button causes speaker relay to click and DBT to flash Marantz 2265

A

Aaron F

New Member
Ive been re capping a Marantz 2265 as well as installing the sparkos labs op amp on the pre amp board PE01.
I had only been getting sound out of one channel after doing the pre amp board but found the mistake was a reversed polarity capacitor at position CE13 ( I know rookie mistake).
Since then I have sound from both channels but the speaker relay will click and my DBT will flash when I press the loudness button or turn the bass knob to about 2 oclock position.
If I turn the button off or the bass knob back to 12 oclock speakers re engage.
Additionally I have been hearing a hum that is only present with audio and gets louder when the bass knob is turned up.
So main problem
Speaker relays disengage and DBT lights up when loudness is pressed or bass knob is turned.
- I have checked the DC voltage on the power supply board and its spec at 35
- Right and Left channel amp DC offset and idle current are set to spec
- I checked the pre amp and power supply boards for cold joints or burnt components and dont see anything obvious.( Im new to this though so my eye isn't great)
- I used the pre out on my marantz 2252 to the main in on 2265 and was able to manipulate loudness and bass without issue.
- So I assume this narrows my problem down to the pre amp or power supply board Im just not sure what to do next.
- The humming noise is also not evident when using the pre out from my 2252.

Appreciate any help!
 
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Putting CE13 in backward may have damaged the opamp HE01. You might try measuring voltages at the pins of the opamp and compare to the schematic. Note that HE01 on the schematic doesn't list many of the voltages, but HE02 - same opamp - does. That opamp is a BA312 which is still available at some of the places that carry older parts. A lot of people replace them with the Sparkos Labs modern equivalent, which is claimed to have much lower noise.
 
So I have the Sparkos labs upgrades already, I emailed the people from sparkos labs and they had me measure a few the resistance of Re 73 which was at the correct value. It was his impression that the Op amps were working correctly.
Could any of the other resistors leading up to it or transistors be the problem?
 
There aren't any other semiconductors in that area of the circuit. It's a long shot, but the output transistors on the PE01 board are known to cause all kinds of problems. HE03 and 04 on one side and HE05 and 06 on the other. It's impossible to say the likelihood of these being the problem. But if it were mine, I would replace all four of them. 2SC1327->KSC1845FTA. 2SA721->KSA992FBU or FTA.
 
Steven Tate said:
I would replace all four of them. 2SC1327->KSC1845FTA. 2SA721->KSA992FBU or FTA
Click to expand...

I had the same thing happen to me (2275) with the relay and bass. I think it's caused by the DBT and the amount of current needed for the bass. I did replace the big filter caps and it didn't do that on the DBT anymore. It also didn't do it when not using the DBT using the old caps & new caps. I use a 120w incandescent in my DBT. I was testing mine after I did the electrical restoration and during music with very strong deep bass passages it pulls about .5 amp. The DBT wouldn't let it pull more than .4, that's when the relay would kick out and the bulb would light...then it would kick back in until the next bass note. I also used the Sparkos Labs upgrade. I also replaced all the caps (film, Electrolytic & Tantalum) and the 4 transistors.
 
Hhhhmmm that could be it, Im only using a 100w bulb. Makes me nervous that it flashes like that to not use DBT, would hate to do more damage. I suppose I could go up to a higher wattage bulb and see if it helps the problem at all.
Ive already replaced all caps on the power supply board and the filter caps.
I didn't replace any of the tantalum caps but I have a lower suspicion that this is contributing to the issue.
 
ttbccw said:
I had the same thing happen to me (2275) with the relay and bass. I think it's caused by the DBT and the amount of current needed for the bass. I did replace the big filter caps and it didn't do that on the DBT anymore. It also didn't do it when not using the DBT using the old caps & new caps. I use a 120w incandescent in my DBT. I was testing mine after I did the electrical restoration and during music with very strong deep bass passages it pulls about .5 amp. The DBT wouldn't let it pull more than .4, that's when the relay would kick out and the bulb would light...then it would kick back in until the next bass note. I also used the Sparkos Labs upgrade. I also replaced all the caps (film, Electrolytic & Tantalum) and the 4 transistors.
Click to expand...
That makes sense. Generally, if the unit powers up, relay clicks, and bulb is dim at low volume, I hold my breath and try it on wall power. Higher volumes will definitely make the bulb brighter, but I'm not sure in your setup what it means. But if bulb dims at idle, nothing should be shorted. May be time to plug it in.
 
I was just going to say I bet the bulb is limiting the power and disengaging the relay. I had a similar issue testing out a Pioneer SX-950 I fixed and restored. It would cut out at louder volumes…took it off the DBT and all good.
 
So the DBT was the issue, I used a higher wattage bulb and the issue resolved. Now plugged into the wall I have no issues at all.
Thanks for the help everyone.
 
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