20070901.ba v04_n085.bam.20070901 >From ???@??? Sat Sep 1 00:01:09 2007 -0500 Date: Sat, 1 Sep 2007 00:00:07 CDT From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4085 Message-Id: <20070901050010.40290470179@srvr1.theporch.com> BOATANCHORS Digest 4085 Topics covered in this issue include: 1) HRO reassembly by "Morris Odell" 2) Re: Dead horse phoenix by wb3fau@att.net ---------------------------------------------------------------------- Message-ID: <000901c7ebc1$42ae4080$ad00a8c0@Morris1> From: "Morris Odell" To: Old Tube Radios Subject: HRO reassembly Date: Fri, 31 Aug 2007 21:22:48 +1000 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Hi all, I have been working on my HRO and have got to the stage of putting it together again. The chassis has been stripped down completely, cleaned, de-rusted and repainted. I have mounted the IFs and tuning components and will be installing the new tube sockets as soon as some ceramic sockets I bought arrive here. I have repainted the front panel ready to install and it looks great. I will psych myself up to disassemble the dial for repainting pretty soon :-) What I need now is some help to get the wiring right. My radio was a dog's breakfast and no clues were to be had from the mess I had to remove. I would really appreciate a few hi-res shots of the underneath of a HRO, preferably the HRO-5 octal version. If any of you can do this for me I'd be very grateful. I also need some confirmation of how the LO grid resistor is mounted. The schematic shows R35 and C30, a 20K/100pf parallel network in series with the grid of V4. In my radio it was a crappy little network that looks non-original, soldered messily onto the appropriate finger of the oscillator coil contact block with the grid cap lead for V4 coming off it. Is this correct? The final question (for now!) relates to the heater balancing resistor R21. This is shown as a 64 ohm 3 watt centre tapped resistor across the 6.3 volt supply with its CT grounded. In my radio it was a thing that looked like a miniature radiator element installed in a very non-professional way on a grubby non-original tagboard on the side of the chassis next to the output tube socket. It seems to me that a couple of 33 ohm half watt resistors would be a much neater and more compact substitute, and could be installed easily in some less crowded area. I would like to know what this looks like in a proper HRO and whether anyone has tried substituting a pair of resistors. The only pics I have found on the web show a rewired receiver with one side of the heater supply gounded. That's it for now, please send any pics to: vilgotch(at)bigpond(dot)net(dot)au Thanks and 73 de Morris VK3DOC ------------------------------ From: wb3fau@att.net To: Old Tube Radios Cc: Scott Robinson Subject: Re: Dead horse phoenix Date: Fri, 31 Aug 2007 18:18:47 +0000 Message-Id: <083120071818.12970.46D85B87000A5EFC000032AA21603763169A0E00CC0D99@att.net> Scott, i will give you a different angle on post-war companies, like Hallicrafters. They were sales driven. Halli sold a lot of gear, mostly because of price. They may have told about the 2 RF amps, but they were not often pushing from a technical advantage. ------------------------------ End of BOATANCHORS Digest 4085 ******************************