ReVox B739 FM Tuner Preamplifier restoration

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John Tulett

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ReVox B739 FM Tuner Preamplifier restoration
« on: 15 Feb 2023, 12:14 pm »
This ReVox B739 FM Tuner Preamplifier I purchased new in 1982, it's a solidly built piece of equipment, weighing a hefty 13 kg.
Recently I completed a full restoration, following picture is only a partial disassembly but gives an idea of what’s involved.


Figure 1. B739 Tuner Preamplifier partial disassembly.

Although you can find copies of the B780/B739 Service Instructions manual on public websites, some of these are low resolution and hard to read.   The best I’ve found for resolution and picture quality is titled “Revox_B780_B739_Serv”, available for download from the Studer ReVox site.
https://www.reeltoreel.nl/studer/Public/Products/Revox/Revox_B780_B739/

General directory for the manuals of all ReVox products.
https://www.reeltoreel.nl/studer/Public/Products/Revox/

Here's a picture of my B739 FM Tuner Preamplifier after full restoration.


Figure 2. B739 FM Tuner Preamplifier after restoration, powered up and operating.


S Clark

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Re: ReVox B739 FM Tuner Preamplifier restoration
« Reply #1 on: 15 Feb 2023, 05:41 pm »
"A full restoration"... wow.  That must have set you back a few bucks.   

orthobiz

Re: ReVox B739 FM Tuner Preamplifier restoration
« Reply #2 on: 17 Feb 2023, 02:34 am »
Labor of love.

Paul

John Tulett

  • Jr. Member
  • Posts: 19
  • Fascinated by vintage audio equipment
Re: ReVox B739 FM Tuner Preamplifier restoration
« Reply #3 on: 18 Feb 2023, 12:06 pm »
"A full restoration"... wow.  That must have set you back a few bucks.

Thanks, please allow me to explain more about this restoration.

Fortunately, the electronic components were standard items and replacements were not expensive, although it took me several months to test and replace each component one-by-one.

Components replaced:
- 23 electrolytic capacitors (many of these measured out of specification and it was essential to replace them all)
- 68 tantalum capacitors
- 1 suppression capacitor
- 1 resistor
- 4 op-amps
- 1 power supply fuse
- 5 pairs RCA jacks (the contacts had become corroded)

Others:
- As the original Nextel paint had become faded and flaking off, what was expensive with this restoration was having the chassis and panels professionally re-painted at an industrial paint shop.  For a small discount I had all chassis and panels for my vintage ReVox equipment re-painted at the same time; B739 FM Tuner Preamplifier mentioned here, B790 Linatrack turntable in my avatar, and a B710 Cassette Deck currently in restoration progress.

Thank you,
John