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Thank you for your kind comment and suggestion.

Thank you for your kind comment. Best of luck with your restoration. Yes, the amp board bows out on mine too. I did wonder about trying to add a central support but in the end I left it as it was. Indeed, those diodes... I have a spare set of the three diode packs but not the four. In anticipation of possibly breaking them (fortunately they were ok) I did some bench experiments with a view to replicating them with a Vbe multiplier - there is a really good video explaining those on w2aew's channel. I did get a circuit breadboarded but didn't take it further. I have a few SX-450s and 550s to restore so as an exercise I might try the Vbe multiplier idea in one of those just to see if it is viable.

Thank you, and thanks for watching the video.

Absolutely, they do look and sound great - definitely a talking point !

@@rossthompson1635 A back story of my Pioneer SX-5590 , Owning and using a vintage 70s receiver never entered my mind until the day I laid eyes on it at a estate sale down the street . I was there to look at a lawn and garden tractor and came home with the receiver and the tractor. While closing the deal on the tractor I entered the house and there she was dialed in to a local FM station , I instantly fell in love with it ,…. At that time I had a Accuphase E-280 a music server , dac and TeKton speakers in my home office, The Pioneer receiver ate the Accuphase intergrate for breakfast, such a fabulous match with the TeKton Lores ..I had it checked out and refreshed it sounds absolutely glorious.

Thank you very much for that kind comment - it was a fun project.

Thank you very much for your kind comment.

Sorry for such a late reply - and thank you for watching the video. Yes, the voltage level of the pre-amp signal internal to the receiver (i.e. after the tone/volume stage but before the power amp) tops out at 1V, but that is with the amp up full outputting 25W, just before clipping. To give an adequate level to drive the amplifier in my subwoofer at normal listening levels (without having to have its own gain maxed out) I had to boost the level of the pre-amp signal; 6dB (double the voltage) was enough in this case. By chance this gave me roughly the same pre-amp voltage level as I measured on a more modern Marantz receiver with a pre-amp out already built in (when both were outputting similar power levels).

Hi, sorry for the late reply. Thank you for your kind comments and for watching the video. I'm afraid I don't know of a source for those knobs, I fear it is mainly a matter of keeping an eye on Ebay, as people sometimes part these units out.

I'm very sorry but I don't - this is just a hobby at present as I have very little time between work and other commitments. Maybe when I retire.... but that is a few years away. I hope you can find someone to get it working properly again.

Many thanks for your very kind comments. I do hope to work on an SX-750 in the new year. Best of luck with your 880.

Many thanks indeed for your kind comments.

Thank you very much!

Thank you for your kind words and encouragement. I would certainly like to do some more videos - as ever, time between work is the tricky thing, but I have more projects waiting.

Thank you. Yes, I feel the same about this one - hanging on to it for sure.

Unfortunately this receiver has some known trouble-makers that just need to go - either to fix faults or for future reliability. When I first turned it on, one of the channels was banging and crackling very badly - this wasn't due to noisy controls but bad transistors. (2SC1451 is a key one that has to go, and 2SA726, 2SC1344 are suspects for going noisy). But yes, I didn't need to replace all of them - the main outputs I think were good, but for me it was partially a case of practice and also for future reliability. If the replacement transistors are suitable equivalents I don't think they change the nature of the sound; I believe most of that comes from replacing capacitors - especially the small electrolytics in the signal path. Because it wasn't working very well to start with I can't really say what it sounded like before everything was changed, I just know it sounds really good now - I'm enjoying listening to everything I have thrown at it so far!

Yes - it does take a bit of research; you have to find a modern transistor (or diode) with a similar specification. A really useful starting point is to look at posts from others who are really experts at this - and for this particular receiver I've (now) put a link in the video description to a specific post from MarkTheFixer on AudioKarma. Otherwise it is possible to download data sheets for old and modern transistors and compare the many parameters for a good match; in the case of the two "pass" transistors in the power supply, I went with some I already had in stock (MJE15030) rather than the suggested ones. (many thanks for raising this as it made me realise I needed to put that link in to the description!).

That sounds like a good deal - I hope you get it up and running.

@@rossthompson1635 This was several summers ago, My favorite lower powered vintage receiver I have.

​@@shannondavis4380Excellent! I think it has become my favourite too.

Thank you for watching from beautiful Canada. (I'm in the UK). Very best of luck with your AKAI project.

Hi, I hope you can get it back in service, they sound really good. For parts, I don't have a full bill of materials as I ordered from a few places as well as using some of my own stock - but I highly recommend the post in this thread on AudioKarma from Mark The Fixer audiokarma.org/forums/index.php?threads/pioneer-sx-636-rushing-sound-on-left-channel.517531/ , which lists suitable replacement components, but I think you will find many of the Mouser part numbers listed will be no longer valid. Then I'm afraid you'll have to trawl through suppliers to see who has what in stock. But you can probably get it going with only some small fixes - I did go a bit overboard with full replacements but it was partially for learning. The main filter capacitors are very likely to be fine. When I got my unit it was popping and banging in one channel but there are some known "replace on sight" small transistors in there that go noisy (again see the Audio Karma thread). The main outputs were fine but for reliability I changed them anyway. I hadn't thought about making the Gerbers available but I am rather caught out by evryone's kind interest in the video - I'll have a think about how to do that. Thank you for watching - and best of luck!

Hi Alex thank you for your encouragement, really appreciated. I would like to do some more videos, I am just amazed with some of the time and trouble others have taken to share their knowledge on TH-cam. As with everyone I'm sure, time is the issue - full time shift work (and recovery from it) leaves me little space, but retirement is looming so output may increase in a few years 😊 Thank you also for your kind offer re. fb, I'm not currently on fb (deliberate choice!) but I may look in to restarting it.

@@rossthompson1635 fb is a mess, so i understand why you don't want it. I use it mostly for messenger to keep in touch with people, Marketplace, and discussing repairs. 👍

They do sound great, thank you for watching.

Thank you, that part was really good fun!

Thank you 😊 Yes I probably did go a bit overboard with the lights. I notice with some mains LED bulbs I am aware of edge-of-vision flicker and that just made me wary. I'm also quite close to the limit of regulation drop-out with rectified 8V AC and a 7V LDO regulator, but unless you really crank the volume to max the lights don't dip in intensity with the beat. Was it the main output transistors you were interested in? I'm going to hang on to those until I get another project completed, but they may turn out not to be required - I'll bear your interest in mind!

@@rossthompson1635 the main transistors yes. You do that 😊.

Thank you - I'm pleased you enjoyed it. I am very new to making PCBs (and these are simple ones) but it is a very satisfying process.