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Little Nipper B13C schematic or similar
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Return to top of page · Post #: 1 · Written at 1:08:30 PM on 6 March 2011.
	BrianC Location: Moss Vale, NSW Member since 6 March 2011 Member #: 850 Postcount: 6
Hi, I have a HMV Little Nipper B13C with a fairly well maintained case, but someone has made some bad repairs to this chassis, and it looks like it has experienced a few caps going open circuit and some other components removed in that repair attempt. The tube compliment is 6BE6, 6BA6, 6AV6, 6AQ5 and 6X4. I'd like to restore this model to add to my collection. Does anyone have a schematic of this or similar layout? Regards, Brian..... ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ Brian C

Return to top of page · Post #: 2 · Written at 11:55:27 PM on 6 March 2011.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5254
That circuit appears in AORSM's I do have a copy of it. Capacitors, if paper, are more likely to have leaked or shorted. I would start by changing every paper cap to 630V metallised polyester & also replace the electrolytics. If you have a valve tester? Check the 6X5 they have a notorious reputation for shorting internally. It does pay to check resistors as you go, remembering that not all can be checked in circuit. I have fixed a few dozen Nippers and some resistors going way out of spec. is not that unusual, Marc

Return to top of page · Post #: 3 · Written at 2:29:39 PM on 7 March 2011.
	BrianC Location: Moss Vale, NSW Member since 6 March 2011 Member #: 850 Postcount: 6
Hi Marc, how do I get a copy of that schematic? This chassis has been hacked at. The speaker is missing, for one thing, then some mods? done where I suspect parts discarded. I have a supply of replacement tubes already for it. I intend to check it out thoroughly including the caps and resistors. Brian..... ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ Brian C

Return to top of page · Post #: 4 · Written at 10:00:44 PM on 7 March 2011.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5254
I know the feeling with hacked sets. I have one (Philips 6501) on the bench. some genius replaced the AZ3 with a 5V4. 5V4 is considerably more efficient. The secondary is 375VAC. So consider 5V4 400VAC gives 470VDC whilst an AZ3 385VAC gives 375VDC No guesses as to why the candohm cooked and I believe at least the leading missing "wet electrolytic" probably exploded and the set was abandoned.. There will be 3 small files. I can email to Brad or Brad can relay an email address mine is in the process of changing. It may prove quicker to fit new parts as you go using the values on the circuit. Do not use supermarket resistors under one watt on the HT, they may not like the voltage. Activated email in profile Marc

Return to top of page · Post #: 5 · Written at 5:08:00 PM on 8 March 2011.
	BrianC Location: Moss Vale, NSW Member since 6 March 2011 Member #: 850 Postcount: 6
Hi Marc, Thanks very much for your input, I will report in progress with restoration of this unit. BrianC ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ Brian C

Return to top of page · Post #: 6 · Written at 5:27:17 PM on 9 March 2011.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5254
Happy to help .--- Things should progress a little more smoothly given a circuit. At least with a circuit you know what should have been where. Having more than enough practice with "Monkyed" sets, it is incredible to see the things that are done. Marc

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