Tomcat1969
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« Reply #345 on: August 07, 2023, 05:21:47 PM » |
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The fact that the fuse blew makes me think that something is wrong with the wiring. Could you take some pictures and post here? Also, pictures where you have tapped into the PCB.
I will do. Thanks very much again. I really appreciate it. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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Tomcat1969
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« Reply #346 on: August 07, 2023, 05:56:46 PM » |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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aboos
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« Reply #347 on: August 07, 2023, 07:03:04 PM » |
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The heater elevation circuitry looks strange to me. There are four cables going in/out: 2 black, one red and one yellow-green. Where are they connected?
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Andreas
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Tomcat1969
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« Reply #348 on: August 07, 2023, 07:15:51 PM » |
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The heater elevation circuitry looks strange to me. There are four cables going in/out: 2 black, one red and one yellow-green. Where are they connected?
The yellow/green goes to ground. The wires at the top of the picture are: black=0v, red 12v. The curved black wire is the B+, 300v. The red and black wires going off to the left are going to the heater for the ECC82. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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niclaspa
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« Reply #349 on: August 07, 2023, 07:53:42 PM » |
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 I guess that not all wires are connected on the picture. The ones that I have marked with a red square is input and output and should be connected to the PCB. The tags marked with green squares should be connected to high tension. The solder tag marked with blue appears to connect ground to the chassis. Is that correct? I think that you have two missing connections marked with the pink lines. |
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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Tomcat1969
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« Reply #350 on: August 07, 2023, 08:01:21 PM » |
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Hi Niclas.  That's right, I disconnected for the picture. Correct, tag marked blue is the gnd rail. Tag marked blue is the HT. The pink lines are connected but hard to see. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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aboos
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« Reply #351 on: August 07, 2023, 10:04:11 PM » |
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Let's recap:
You have got a blown fuse and burning resistors, this means current in the buffers is way too high! And it seems both channels are behaving identical as both 18k resistors show signs of overheating.
What is the rated wattage of the 18k resistors? In normal operation, they will dissipate around 2.5 W. To avoid any overheating their nominal rating should be 4 W or higher. Please check if they still measure 18 kOhm or if they are already burned.
And what was the time between glowing heaters and blown fuse?
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Andreas
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Tomcat1969
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« Reply #352 on: August 08, 2023, 10:28:27 AM » |
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Hi Andrea's. The resistors are 2W only. I think between 1 and 2 minutes till the fuse goes. When it was first switched on there was a very bright light in the valve, almost white in fact. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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niclaspa
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« Reply #353 on: August 08, 2023, 12:22:17 PM » |
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A valve lighting up brightly on switch on is normal. Some samples behave like that.
The resistors dissipate 1.15 W each. It is best if you replace them with 3 W or 5 W resistors, but they shouldn't burn like that if everything was right and the fuse certainly shouldn't blow.
I think that some measurements would be helpful. Could you measure the heater voltage with the valve in place? Also, the voltage between the cathodes and ground and the voltage between anode and ground.
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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Tomcat1969
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« Reply #354 on: August 08, 2023, 12:47:54 PM » |
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OK, I'll do the measuring a bit later. Thank you.
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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Tomcat1969
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« Reply #355 on: August 08, 2023, 05:02:48 PM » |
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I'll wait for a couple of days gentlemen. The 10M resistors I have here are all pretty variable, I should have been measuring as I went. Almost out of solder as well.
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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aboos
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« Reply #356 on: August 08, 2023, 08:35:37 PM » |
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Looks like the grid voltage is higher than expected. In this case, voltage over the 18 k resistors will go up as well and power dissipation increases rapidly. With e.g. 220V they already dissipate 2.7 W.
So when doing measurements, you should perform them quickly after powering up to avoid destroying parts.
One possibility for a drifting grid / cathode voltage can be grid current of the valve in use as the grid resistors are quite high at 10 MOhm each. To check for this possibility, connect your voltmeter over the 18 k resistor, then switch on and observe the voltage. With the heaters warming up, voltage should slowly go up to 150V and then stay stable. You can't measure the grid voltage directly due to the high impedance and the voltmeter with a 10 MOhm input impedance will already reduce the gridvoltage to 100 V only!
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Andreas
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Tomcat1969
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« Reply #357 on: August 31, 2023, 08:20:38 AM » |
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Success! Almost. I decided to rebuild the buffer and heater elevation circuits. It works, but I am getting a strange sound in the right channel after about ten minutes play. Like a rustle of a large paper bag.  More investgation required. I swapped valves around on Vlads board and it came back in the right channel. I think I have another ECC82 to swap in to the buffer but I'm not sure. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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niclaspa
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« Reply #358 on: August 31, 2023, 08:49:25 AM » |
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Success! Almost. That is nice to hear! It works, but I am getting a strange sound in the right channel after about ten minutes play. Like a rustle of a large paper bag. It could be a bad solder joint. |
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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Tomcat1969
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« Reply #359 on: August 31, 2023, 08:55:07 AM » |
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That is nice to hear! It could be a bad solder joint. Thanks Niclas. I'm pretty happy with it. I'll investigate further today. It's hum free, despite my layout, it's fugly. |
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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