In 2010 when I first launched my RA17 restoration service, I had refurbished only two of these classic receivers … both of which were relatively early MK1s. At the time the price that I came up with was based on what RA17s were selling for on Ebay plus the cost of parts and a little bit extra.
Over the subsequent years I have been repeatedly told that I was under-charging for my services and that I should increase the cost of the service to more accurately reflect the amount of work entailed. This was something that I stubbornly resisted … up until now that is.
I recently counted the number of RA17s and variants that I have fully refurbished since 2010 and was somewhat shocked that they total no less than 22 at time of writing. These include 9 MK1 and MK2s, 10 RA17Ls, 1 RA17W, 1 RA117 and 1 RA117E. I think you could say that I have served my apprenticeship!
What does a full refurbishment and realignment actually entail?
When a receiver comes in for refurbishment, it is fully examined for any missing or extra parts. Some things are more obvious than others. When like me, you have taken apart and re-built over 20 RA17s you know exactly what to look for.
My refurbishment policy is based on the premise that over time, components degrade. This is well known regards tubular wax/paper capacitors, but not many people appreciate that 1950s resistors also degrade, especially if they are ‘stressed’. The effect of degraded capacitors is often immediately apparent. With paper capacitors the inter-layer insulation (paper and wax) dries out and the capacitor behaves more like a resistor. When this happens, the capacitor is said to be ‘leaky’. A consequence of this is heat, since the capacitor is now resistive. Sometimes this heat can have catastrophic results with the capacitor literally exploding out of its can. More often than not though, it simply oozes horrible brown wax all over the inside of the receiver. This is sometimes accompanied by a sticky dark smoke. As said, the resistors in the receiver are also prone to degradation. By their very nature they incur some thermal stress. This is often compounded by the presence of ‘leaky’ capacitors which are drawing current. The overall effect is cumulative; a factor that is often overlooked. My own personal experience is that in any RA17 with pre-1970s resistors, 30% will be high in value. And of that number 30% will be anything up to 100% high; some a lot higher! These statistics actually decrease with later models. However, the composition of the resistors also plays a part in the receiver’s ultimate performance. Towards the end of the type’s production run, RA17Ls were achieving noise figures far in excess of specification. This was very likely to be due to general improvements in component quality … notably resistors. RA17s that I have refurbished, likewise demonstrate even better noise figures than late model RA17Ls. This I believe is due to the continued improvement in component quality today.
Thus, it is my policy to replace ALL the carbon resistors throughout the receiver as well as ALL the tubular capacitors of 10nF upwards. In doing so, not only are numerous imbalances corrected but the life of the receiver is also extended … some might even say indefinitely … as long as you can keep the heaters glowing!
Speaking of valves (or tubes), the RA17 also contains something in the region of 25 valves, depending on model. These will be individually tested on my MK2 AVO Valve Tester. Any valves found to be below standard or showing signs of inter-electrode leakage will be replaced for a nominal fee.