Trouble with my Paramounts [resolved]

[patm]

Hello,

I posted about this problem maybe 8 months ago. One of my Paramounts just stops playing music. When I get a look at it on the workbench, only 1 of the LEDs is on. In the process of checking voltages the other three LEDs come on. There seems to be no rhyme or reason to LEDs coming on. (I'm sure there is to someone more skilled). The only voltages that are out of line are:
#  Me    BH
9.  150.  195
19  152. 195

Before when the LEDs came on during testing I put it back in the system and it worked for 8 months. Now it makes a scratching sound intermittently and then quits playing music. Tubes are on.

While on the workbench I did a chopstick test and never could make the LEDs turn off.

Help

Pat McSween

 

[Paul Birkeland]

In the process of checking voltages the other three LEDs come on.

This is almost always a flaky solder joint or a broken wire.  I would start by reheating every solder joint the amplifier.  Does this behavior occur no matter where you are checking voltages in the amplifier, or only at certain spots?

 

[butchbass]

I had a similar problem with my Foreplay III. It turned out to be a bad solder joint on one of the capacitors in the HV power supply.

 

[patm]

Thanks for the replies, I will dive in tomorrow.

 

[patm]

Hello,

The good news is that I found the intermittent problem I think. Black wire from r b twisted pair ps board to 16U was broken under the board, only found it when I tried to move the wires to install soft start kit.

My issue now is that this was a 2010 kit, prior to the 2011 change to the kit. I have one ss board installed and the other board is ready to install and I have 4 of what is described on page 15 of my manual as a 220 ohm 1/4W carbon composition resister (r,r,br,go). And I have two larger resisters that also test in the 220 ohm range with the same color code (r,r,br,go). On page 20 of my manual, it asks me to install a 220 ohm carbon composition resister (r,r,br,go) from B7 to 18L.
The next step asks me to install a 220 ohm carbon composition resister (r,r,br,go) from B3 to 20L. In the picture I can clearly see that the resisters are different, the one from B3 to 20L appears to be like the 1/4W one from pg 15 and the one from B7 to 18L is like the larger resisters I have 2 of left.

I am officially confused. Help

Pat McSween

 

[Paul Birkeland]

It would help to see a photo of what you have. 
-PB

 

[fullheadofnothing]

They are all 220Ω resistors. Look at the color codes. The two in the manual are probably from different batches, but they are clearly 220Ω carbon comp resistors. Use what you have.

 

[patm]

Thanks for the prompt reply.
I guess one of the things I was worried about was that I appear to have 2 many resisters left and the other thing was that there might be different watage requirements.

My camera bat is charging, post pic when charged.

I haven't applied power yet. I will wait untill I post the pic.

Pat

 

[patm]

This what I have

 

[Paul Birkeland]

The larger ones will fit on the sockets just fine.  My guess is that the 1/4 watt parts were out of stock (they take many, many, many weeks to get from the factory when the suppliers run out), so two 1/2 watt parts were added as substitutes.

 

[patm]

Thanks,

You guys rock. I must admit that some times I am afraid you guys will find out how little I know about this stuff and kick me out.

I installed two of the 1/2 watt ones in the 9 pin of the modded amp so I will install the remaining two in the other amp 9 pin.

I will apply power and volt ck tomorrow morning when my head is clear.

Pat

 

[Paul Birkeland]

The 1/2 watt parts are actually a lot stronger physically than the 1/4 watt parts, and they should hold up a lot better to being mounted to a 9 pin socket.

 

[patm]

OK,

The intermittent amp has been modified (SS kit) and everything checks out and it playes music.
Finished installing the kit on the other amp. I have 299.7 volts at pad OB and the trim pot is unresponsive.

 

[Paul Birkeland]

What's your Kreg A voltage?

 

[patm]

8.4vdc

 

[Paul Birkeland]

Check your jumper that's Kreg to Breg.

 

[patm]

I get 8.3vdc at breg (Kreg to breg A side) I just noticed the LEDs are not lit on B side.

 

[Paul Birkeland]

I would just double check your work against the working amp and the manual.  A backwards TL431 could also present some strangeness like this.

 

[patm]

Ok, I went through all the steps and everything is installed correctly. Noticed what might be a bridge between pads IB and OB, cleaned it up with some braid. Touched up the transistor soldering and OUTSTANDING, turned on power B side led's lit. 5670 plate voltage came right in to 175vdc.

Listning to music now. Sounds wonderful as usual.

Thanks for all the help. I think it might be time to hang up my soldering iron. Some of the medication is slowing me down and my last two builds have been wrought with problems. Although, it is job security for you guys if I keep building kits.

I have arrainged for Shawn to build the Eros that I havent started yet.

Thanks again,
Ps: even if I quite building kits, I will definitely stick with BH gear.

 

[Doc B]

You are most welcome, Pat. Congrats on getting it running.