It's another post on the Walkman Tech Talk part of the forum. You know what that means... Time to spill the beans on another successful AIWA rescue.

As a reward for servicing an AIWA HS-JL30 recently I received a nearly mint but barely functioning AIWA HS-RL50. This unit is a real beauty. It is rare enough that it is a Japan only model (I don't think any variants exist outside of Japan - Someone will probably prove me wrong), but this particular one is in an especially rare silver colour too! Sadly with just about every AIWA I've received, this one too has suffered from leaked electro caps, luckily for me it wasn't as bad as another RL50 that I have (Yes I have the black one too). The black one is completely dead from excessive leaked capacitors

The problem with the poor old RL50 is that AIWA in their infinite wisdom designed it (and the PL50 from which is based on the RL50) wholly using surface mount capacitors. These types of capacitors have fared the worst for leaking over the through hole types over time and caused some of the worst damage too! I have a PL50 that is completely soaked in leaked cap fluid which needs rescuing at some point.

Removing the back cover of the unit exposes the circuit board. There is leakage from the capacitors, but thankfully it and any corrosion is restricted to the proximity of the capacitors.

Lifting the main printed circuit board (PCB) reveals that at some point someone has had a tinker about inside. Notice the bodge job where someone has used a through hole capacitor located next to the two small surface mount capacitors. The black RL50 has a 47uF 4V surface mount capacitor in this location. Also notice in the middle right of this picture someone has moved the six pin surface mount IC chip. There is a reason why someone did this (more on that later), but it is a poorly executed job nonetheless.

There are areas of dried harded electrolyte as can be seen from the darker areas on the board such as just the right of the headphone jack. From a distance this looks like old flux. If you put a soldering iron near this stuff you soon know it is not, from the acrid smell given off.

All the surface mount capacitors are removed. They were later tested and found to be all dead. Next to no readings from a capacitance meter and resistance readings off the scale on an equivalent series resistance (ESR) meter. The acid within the leaked electrolyte has lifted the screen print from the main PCB.

The switch control PCB, volume potentiometer, flexible flat calbles were also removed to aid cleaning

The majority of the flux was swabbed off using isopropyl alcohol. Then a generous amount of Sodium Bicarbonate was mixed with water to form a paste and gently brushed onto the main PCB and left on to neutralise the acid. It was then rinsed off and followed with a wash of mild dishing washing detergent to de-grease the main PCB. All the loose screen print has regrettably floated off down the sinkhole.

The board was reassembled.

So what of that six pin IC chip? Well it turns out, the reason why it was repositioned by someone, was because if left in the correct position as per on the board it would actually rub on one of the flywheels! I tidied up the soldering on the IC chip and straightened its position on the main PCB.

How does it sound? Well this has to be my favorite ALP transport based AIWA for listening to the radio. It has a variable controlled BBE switch delivering customisable levels of treble and clarity where I need it. It has higher spec'd 330uF DC blocking capacitors offering deeper bass with DSL activated. The DSL is actually balanced and sounds good enabled even on my bass heavy IEMs. With it being based on the PL50 it also shares the same amplifier IC chip and therefore has the higher power output levels than the recording AIWA models. The manual tuner despite not having a proper international scaled FM is tunable through the entire range and is very sensitive. Being a Japanese model, it also has a TV band as well as AM band.

This is a very rare model, and made especially rarer still by the silver colour. I am honoured to have it fully working in my possession.