Hagerman Cornet2 Not Working Left Side

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count123

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Hagerman Cornet2 Not Working Left Side
« on: 25 Mar 2011, 09:43 pm »
I'm new to this site and need some help in completing my Cornet2 phono stage.
Hooked up my Cornet2 and Left side is not working.
Run down, what I checked and did:
Checked resistors values and position on board. All checked within range except R200L
which showed .3 ohms.  R200R  showed 47K on DVM.  Replaced Left input connector and
made sure wasn't in contact with chassis. Made no difference.
Changed tubes 3 time. Still nothing.  Changed rectifier to 5AR4 which increased voltages
at points.
Fil. Volt.- 6.23          Voltages at R107-367v
            L                                     R
R219-- 160v                                154v
R212--152v                                 145v
R211--335  -308v                         333  -306v
R204--167v                                 184v
Jim says it's shorted on the input side but I don't know where to look.  Hope someone can help.   Chester                                   

poty

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Re: Hagerman Cornet2 Not Working Left Side
« Reply #1 on: 26 Mar 2011, 12:34 pm »
You should look at the input side as Jum suggested. You know where to find the R200L - you measured its resistance. Check all solder joints, intertrace shorts, miswired places around the resistor. You can trace where the R200L connects to just following the traces on the PCB. Have you checked the resistor without the left RCA soldered? Have you tried to unsolder the resistor and check it alone?

count123

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Re: Hagerman Cornet2 Not Working Left Side
« Reply #2 on: 26 Mar 2011, 01:28 pm »
Thanx for the reply poty.
Yes, I have checked the resistor without the RCA. Made no difference.
I unsoldered the resistor out of the board, it was good at 47k ohms.
Put in a new one in case, made no difference.

poty

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Re: Hagerman Cornet2 Not Working Left Side
« Reply #3 on: 27 Mar 2011, 12:33 pm »
According to the Cornet 2 schematic there are only 3 "destinations" from the upper (not grounded) side of the R200: S200 switch, input jack and R201. It is fairly easy to track where the "point" is connected to the ground (solder bridge connection, bare wire touching the ground plane...). Maybe you tested wrong side of the R200L?

count123

  • Jr. Member
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Re: Hagerman Cornet2 Not Working Left Side
« Reply #4 on: 27 Mar 2011, 07:26 pm »
Took the Cornet apart again to check for bad solder joints and bridges.
Touched up a few joints but saw no solder bridges. Still nothing out of left channel.
Got the magnifying head set and checked the trace from RCA connector.
Found a input copper trace bridge to the one beside it. Used a dremel tool
to separate them. The DMM showed 47K ohms at R200 on the left side. So I think the problem is solved. Now, just to assemble it together again.
Poty thanx for your help. Now to see what everbody is raving about.

poty

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Re: Hagerman Cornet2 Not Working Left Side
« Reply #5 on: 28 Mar 2011, 06:54 am »
Got the magnifying head set and checked the trace from RCA connector.
Found a input copper trace bridge to the one beside it.
Sounds that your board has a defect.

count123

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Re: Hagerman Cornet2 Not Working Left Side
« Reply #6 on: 28 Mar 2011, 11:31 am »
Yes, it was just a dot but caused a huge headache.  Never thought of checking the board
before I started.  Hope there's no other problem 'cause I still haven't fired it up.

count123

  • Jr. Member
  • Posts: 12
Re: Hagerman Cornet2 Not Working Left Side
« Reply #7 on: 29 Mar 2011, 08:02 pm »
Just finished putting everything back together again. Hooked it up to my linn.  Sounds really good.  Will let the caps. burn in before the real magic comes out.
I had build another phono preamp, using 6sl7's, separate power supply with 2 chokes and I think the Cornet already "mops the floor with it".
But both are new, time will tell which is better in the end.