Power supply HP182T - UK Vintage Radio Repair and Restoration Discussion Forum

mimmo2010 · 22nd Oct 2014, 11:12 am

hi, I have a problem with the power supply Hp182T, after about 10 minutes of operation, the correct value of +100 volts starts giving values ranging from 88 volts to 97 volts and not 'more stabilized, may depend on what ??
regards

threeseven · 22nd Oct 2014, 11:44 am

Have you checked the output voltage with an external meter? What type of meter does the power supply have?

Herald1360 · 22nd Oct 2014, 12:11 pm

HP182T is a scope mainframe.

Manuals seem to be available from the usual suspects.....

Humber888 · 22nd Oct 2014, 2:46 pm

All the LV power supplies are referenced to the +100V one. The +100V supply gets its reference from a temperature compensated zener. So, are the other supplies varying as well? Where are you measuring the +100V rail? The best place is at the +100V test point on the mainframe regulator board. This is easily accessed by removing the locking cover on the bottom rear of the 'scope. (Don't remove the cover while the 'scope is on.) Also, is your measurement taken with the plug-ins inserted? If so, switch off, unplug them, switch on and then see if the 100V rail continues to vary.

Mike

mimmo2010 · 23rd Oct 2014, 8:15 am

Hello Mike, I have already changed the electrolytic capacitors in the output, a resistor A1A2R9 33,2k be replaced with BC337 transistor 2n3704 A1A2Q2 fault because it worked fine a couple of days with stable voltages, then began to make the default. I think it is not good that the BC337 !!
I found the horizontal amplifier and two resistors routes A5R38 A5R55 from 22,1k.Le test I'm doing a vacuum extract the power from Hp182t.
I tried plugging a lamp as load to 60watt although there are 90 volt output will not turn on.
volts have been taken in the points test
regards Thanks
Mimmo

mimmo2010 · 28th Oct 2014, 11:19 am

Sorry for the delay, everything is ok, the problem is solved I replaced the BC337 with a 2N3704 and the voltage is back to normal.
Thanks to all

22nd Oct 2014, 11:12 am	#1
mimmo2010 Retired Dormant Member Join Date: Jul 2014 Location: Rome, Italy. Posts: 23	Power supply HP182T hi, I have a problem with the power supply Hp182T, after about 10 minutes of operation, the correct value of +100 volts starts giving values ranging from 88 volts to 97 volts and not 'more stabilized, may depend on what ?? regards

22nd Oct 2014, 11:44 am	#2
threeseven Octode Join Date: May 2010 Location: Worcestershire, UK. Posts: 1,880	Re: Power supply HP182T Have you checked the output voltage with an external meter? What type of meter does the power supply have? __________________ BVWS member

22nd Oct 2014, 12:11 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Power supply HP182T HP182T is a scope mainframe. Manuals seem to be available from the usual suspects..... __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

22nd Oct 2014, 2:46 pm	#4
Humber888 Heptode Join Date: Jul 2012 Location: Bromley, London, UK. Posts: 702	Re: Power supply HP182T All the LV power supplies are referenced to the +100V one. The +100V supply gets its reference from a temperature compensated zener. So, are the other supplies varying as well? Where are you measuring the +100V rail? The best place is at the +100V test point on the mainframe regulator board. This is easily accessed by removing the locking cover on the bottom rear of the 'scope. (Don't remove the cover while the 'scope is on.) Also, is your measurement taken with the plug-ins inserted? If so, switch off, unplug them, switch on and then see if the 100V rail continues to vary. Mike

23rd Oct 2014, 8:15 am	#5
mimmo2010 Retired Dormant Member Join Date: Jul 2014 Location: Rome, Italy. Posts: 23	Re: Power supply HP182T Hello Mike, I have already changed the electrolytic capacitors in the output, a resistor A1A2R9 33,2k be replaced with BC337 transistor 2n3704 A1A2Q2 fault because it worked fine a couple of days with stable voltages, then began to make the default. I think it is not good that the BC337 !! I found the horizontal amplifier and two resistors routes A5R38 A5R55 from 22,1k.Le test I'm doing a vacuum extract the power from Hp182t. I tried plugging a lamp as load to 60watt although there are 90 volt output will not turn on. volts have been taken in the points test regards Thanks Mimmo

28th Oct 2014, 11:19 am	#6
mimmo2010 Retired Dormant Member Join Date: Jul 2014 Location: Rome, Italy. Posts: 23	Re: Power supply HP182T Sorry for the delay, everything is ok, the problem is solved I replaced the BC337 with a 2N3704 and the voltage is back to normal. Thanks to all