Having free time is good sometimes and to repair this AIWA I eventually found out I was going to need a fair bit of time to dedicate it's revival that it deserves...

I had read reports from various places that the AIWA HS-PX505 was one of the finest sounding walkman that were ever produced at the time. Being a great fan of AIWAs I knew I had to get one to see what all the fuss was about. It was tough going. This model either must have been so good that nobody wanted to give it up or never sold in great quantity or the failure rate was so high that most of them must have simply ended up in the bin. After a long search I finally managed to acquire this example from Germany. The chap that sold it claimed that it was in very good working order, and it was fully functioning. I had to ask as I got a HS-PX30 from Japan and the logic on that was completely toast. Maybe one day I might have a go at fixing that one too, but for now that will remain in the "very hard to repair pile".

A couple weeks later and the HS-PX505 turned up. I took it out of the parcel and set it all up ready to play my test tape. Oh... not quite exactly as the seller advertised. The logic was screwy. Play kind of worked. Rewind went fast forwards and Stop well it didn't stop. In fact the unit decided it only really wanted to do a combination of either play or fast forward.

It did eventually play properly however - albeit momentarily. Well, I could tell that the capacitors in the HS-PX505 were not sounding the best owing to the crackle and static as they warmed themselves up. Despite this, I can see why anyone who has ever heard one of these raves about them. The sound is so sublime.

I just can't get enough of the variable slide BBE. This was how BBE should have remained, not the later all or nothing cheaper versions that AIWA knocked out in order to save on cost. With the slide I can add precisely as much as I wanted. It works really really well with Dolby C recordings - Added clarity and brightness with minimal hiss. I have to go as far as saying that on some walkmans it is very hard to notice high bitrate MP3s recorded onto tape, but on the HS-PX505 - you can tell. Even with the worn out caps the two stage DSL is not so bad. Stage 1 is well measured and stage 2 not boomy as like implemented on a Sony through DBB. This may all sound even better when I get good caps for it. If going by the JX505 that I previously repaired.

Well having tried the listen test it was time to have a poke inside. I opened her up and to my dismay the circuit board was swimming in leaked electrolyte. Thankfully it had not dried into a white salty crust like that I had found on the JX505. It was amazing that the HS-PX505 had even fired up let alone sounded as half decent as it did. There were pools of leaked electrolyte all over the logic transistors and all over the tape mech IC too. i could see that some of the traces on a couple of the caps weren't looking good. My heart sank. This was not going to be a straightforward refurb. At least this went some way to explaining the crazy behaviour from the logic controls.

I removed the bad 47uF, 100uF, and 220uF caps as I had replacements for these. The two 470uF caps were worn out and leaky too, but would have to wait for a future order from Digi-Key to be made before I could replace them. Sadly I lost two of the pads on two capacitors in the process. The acid had eaten through the traces and weakened them.

The board was then given a good dosing of Bicarbonate of Soda to neutralise the acid and washed down. A few quick blasts of compressed air and then left to rest in a nice warm place to eek out the last of the moisture.

Inspecting the board afterwards there were some very dodgy looking and potentially dry solder joints. They looked dull and some were very heavily oxidised. I re-tinned the majority of all the connections. I also replaced the capacitors that I taken out and re-routed the capacitors from where the pads and tracing were missing.

Powering up the HS-PX505 now the logic control works as originally intended. Inserting a tape the tape slack is taken up and it waits for your next command. Pressing Play returns a solitary BEEP and playback begins. Pressing Play again and two BEEPs confirms reverse playback. Pressing Stop and it confirms with another BEEP. An interesting detail I have discovered is that when winding tape fully back to the beginning completes, the logic then plays the cassette. Nice touch AIWA.

The repair is nowhere complete, I still need to replace those 470uF caps. and give the tape mechs a full clean up to name just a few things on the to do list, but for now the HS-PX505 is looking a lot better than when I got it.

The story continues...

This... is why I love and hate Aiwas.

About capacitor pads ripping off because they are weak... SO TRUE.

Now everytime I find an 80s/early 90s Aiwa, I always tell myself: It's always broken.

I'm actually more surprised when I find an early 90s walkman that is truely still working with it's original parts. Only ever stumbled over a couple of those out of the majority that I have.

I've got a 90s PX347 Aiwa work straight off as well. Low volume levels, but it's quite nice.

Caps I suspect.

On the other hand, Late 90s/Early 2000s era Aiwas are a different story. As Aiwa began to cheapen out (especially after the Sony takeover), the machines became simpler, plastic and thick. And guess what? Every single one that I have works. And they don't sound too bad either.

One of them is a Singaporean made HS-GM100. Looks undesirable and unassuming but on closer inspection, has the same head/transport as the late 80s/early 90s machines (play button in middle, DIR/stop/rew/ff on right). Quite the surprise they decided to resurrect this design. The only part they changed was switching from the Namiki motor to a cheaper generic one.

I agree there was period when AIWA did seem to recycle their designs and in many cases cheapened out the component count in subsequent models. They didn't seem to be the innovators that they once were. Take for example the HS-PX410. It basically has the same tape mech as the much older HS-P50. Even the switch placements are in the same locations on both models. This would have saved them design and re-tooling costs too.The HS-PX410 had the potential to be a very capable latter day Dolby C player, but it lacked the remote controller and had a cheaper standard fixed azimuth tape head fitted instead of the azimuth adjustable HX head. It also lacked a rechargeable (NiCD or Lead acid) battery feature. All features on the previous P50 model. So why go to the bother to create a supposedly higher end Dolby C player and omit the nice to have features. Cost saving I'd suspect and all under the stewardship of Sony accountants.

Their newer high end models towards the end were just basically re-badged Sony models. Also by the end the naming convention of the model ranges were getting quite confusing and no longer followed any kind of logic or order, probably also another result of it's new owners.

It has been a while since I updated the forum with regards to repairing the PX505.

I took the decision to replace all the non-audio path related capacitors with tantalums. This left only the two 470uF 2.5V and the three 100uF 4V capacitors.

The 470uF are DC coupling capacitors that determine the bass roll off and are a close approximation to the original 470uF 2V they replace.

The 100uF are responsible for filtering out noise from the playback head. Both left, right channels get a capacitor . Even the ground from the playback head gets a capacitor too!

The tantalum capacitors seem to have reduced the motor hum to a greater amount.

I also looked at the possibilty of converting the fixed playback head to a bi-azimuth mechanism. After dismantling the PX505's alpha tape mechanism and rebuilding it back again, I can conclude that unfortunately there is no easy way to cannibalise parts from other alpha based models with the bi-azimuth mechanism to use in the PX505. I examined the mechanism from PX303, PL30, JX505, JL50, and F505 models. The PX303 is the closest in length, but AIWA made a change to a rivet location on the PX505 and this rules out using the parts from a PX303. The 505 bi-azimuth models have the rivet in the correct position, but the alignment plate is much shorter on the PX505 than the 505 bi-azimuth models. I do not rule out the possibility of a bi-azimuth modification though, as someone who is able to work with steel plate would be able to re-rivet the older adjustment screws onto the PX505 adjustment plate. The heads from a PX303 are compatible with the PX505 and could be installed. AIWA even allowed for a hole in the PCB to facilitate head alignment.

I still have a good working Aiwa walkman HS P705, but the battery (PB S5) does not charge any more. I heard that it is no more made and found. Is there a similar battery on the market ? It has a DC 2V 280mAh power.

Can somebody help me ?

I am not sure as to why you have decided to hi-jack this thread in order to flag your need for a part that is not even used in the PX505.  The issue of the PB-S5 battery has been discussed at great length on this forum in various related threads (of which this not one of them) as no longer available for general purchase.

I appreciate that you are a newbie, but please in future if you want to ask the forum a question to either start a new thread or post into one that is at least relevant to the subject matter rather than posting your demands in random threads.

Is there someone who can recommend a place I can eventually getting my Aiwa serviced

AIWA HS-PX505

Thanks

Bryan

( ask about his Aiwa service )

http://www.ebay.com/itm/Sony-cassette-walkman-repair-service-/111031081482?pt=Cassette_Players&hash=item19d9f7da0a