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New Project Marantz 2250b
New Project Marantz 2250b
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Old 23rd December 2017, 07:48 PM   #1
pjf610 is offline pjf610
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Default New Project Marantz 2250b

Hi all, since i am waiting for a replacement power switch for my 2216b, i am going to start getting into my 2250b So i turned on the 2250b (using a DBT) and it turns on no problem but no sound i did notice that the relay did not switch on, before i start cleaning things up, what are the first steps to see what's going on, I did notice there were no jumpers between the Main and Pre amp so i made up a set yet still no relay turning on. Where do i begin.

Thanks Pat
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Old 23rd December 2017, 07:54 PM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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First thing to do is find out why the speaker relay is not switching.
Probably DC on the speaker line. Check around HB05/6/7 if there is no DC on the line.
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Old 23rd December 2017, 08:18 PM   #3
pjf610 is offline pjf610
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Are the HB05/06/07 on the power board??
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Old 23rd December 2017, 08:51 PM   #4
phase is offline phase  United States
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Could you use the pre-outs to test for dc offset.

J807-J810 are on the power board, appear to be the in/out of the relay, the schematic is on hifiengine to be sure.

Last edited by phase; 23rd December 2017 at 09:05 PM.
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Old 8th January 2018, 09:17 PM   #5
pjf610 is offline pjf610
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Hi what is the procedure for checking the DC offset on this unit???

Pat
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Old 27th January 2018, 06:06 PM   #6
pjf610 is offline pjf610
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OK I started to go over this unit i knew there was a problem when i got the unit!! The first thing after checking some of the voltages was to test the output transistors (I took them off and tested them) the right channel was ok the left had both transistor showing there were shorted, I changed them out with new transistors and when i put the unit back on the DBT VERY BRIGHT light, I am trying to determine were to start troubleshooting, were do i begin???
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Old 28th January 2018, 04:54 PM   #7
pjf610 is offline pjf610
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I think i was able to isolate the problem to the left channel, I pulled out the 2 new transistors and turn on the unit and the relay clicked on, some people on the site said that the H701 and R713 have given them problems I do not want to guess but knowing that the problem is in that channel what would be my next step???
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Old 28th January 2018, 05:01 PM   #8
Mooly is offline Mooly  United Kingdom
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New Project Marantz 2250b
Just check if the voltage across H701 is correct. It should be similar to the good channel.

Driver transistors could be favourites if the outputs had failed short circuit.
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Old 28th January 2018, 05:07 PM   #9
pjf610 is offline pjf610
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Hi Mooly, thanks for the come back, should i check the voltage live or in the off state??
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Old 28th January 2018, 05:26 PM   #10
Mooly is offline Mooly  United Kingdom
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New Project Marantz 2250b
Do a quick static resistance check first (amp off) and see if they seem leaky or short.

If they are OK then we short out the bias generator and do voltage checks with the amp running.
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