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I'm finally going to try to address an intermittent right channel loss when using Aux or Phono inputs. I've seen threads describing how to cut off the ends of the ribbon cables, strip back the insulation, and re-connect. I had thought it was a ground problem, but re-soldering the grounds did...

I inherited a Dual 1019 without a base/plinth. I've done all the recommended service work and have it working nicely, at least from a mechanical standpoint. I've also built a base and cut out a new plinth for it. Unfortunately, the mounting for the phono jacks is broken, so I am extending...

I just purchased the Fosi BT20A Pro (48V version) to replace a traditional AB amplifier which had been driving two pairs of remote speakers - the built-in units in our kitchen and another pair out on our deck (two pairs, total, both rated at 8 ohms nominal). My primary goal was to reduce the...

I run across an occasional glitch when using Amazon HD (aka Amazon Music Unlimited), and was wondering if anyone is aware of a way to report such issues and (hopefully) get them corrected. Some examples: 1. Several songs that are part of playlists I've built have very long dead spaces at the...

Hello. I picked up an MX-630 for a system I'm putting together for my brother. I am thinking about replacing the electrolytics as a preventive maintenance measure, even though Yamaha used very nice caps in their original build (including a lot of Nichicon Muse). In doing some initial clean up...

I recently picked up a Yamaha MX630, and already had an MX800, which does a good job in one of my secondary systems. I plan to use the MX630 in a system I'm putting together for my brother. I've not examined them closely yet, as my workbench is a bit crowded right now, but I'm wondering about...

For several years, my beloved AU919 sometimes drops the right channel. This occurs only when using components connected to inputs controlled by the input selector. It does not occur with components connected to the Tape In jacks. This is primarily an issue when using the phono inputs (either...

I am working on my second restoration of an AU-717. After making some initial repairs, this was a working unit. For my first restoration, I followed the @Leestereo restoration thread and after a few hiccups, it turned out very nicely. This time, I decided to go all out and replace just about...

I'm getting confused about how to connect a single bipolar cap to replace a series pair of polarized caps on the tone board. So far, I've assumed that connecting the legs of the new cap to the two negative soldering points is the way to do it, but now that I'm thinking (over-thinking?) about...

I'm wrapping up my second overhaul of an AU-717, and a couple of thoughts crossed my mind (pretty busy day in there, relatively speaking). First thought was "dang, this thing was more work than I remembered". Second thought was how much I appreciate all the folks in this forum who share their...

I'm doing my second rebuild of an AU717, referencing the great @Leestereo and @Super Noob threads. This was a working unit (after some minor repairs). I completed the driver boards, re-installed them and set bias and DC offset. All good so far. Then removed the power board and rebuilt it...

I have an Optonica SM4646 dual mono integrated amp which uses the Sanken S-80W integrated output modules. It is a good sounding amp used in one of our secondary systems, driving a pair of KLH Fives mostly for background listening. I replaced all of the electrolytics two years ago, along with...

I am working to update a nice Optonica SM-4545 integrated amp. I've restored/rebuilt a number of amps over the years, with the generous help of the AK technical brain trust, but I've never run across inductors like I've found on the power supply/protection board of this unit. Normally I would...

I'm doing some updating of an Optonica SM-4545, and thought that I might replace the protection relay while I am at it. However, I don't know how to determine the correct version. The existing relay is an Omron. On the top of its case it says Type MY2. The internal wrapper of the coil is...

I've read over the years that replacing caps in tuners can cause problems with alignment. I've been working on restoring/rebuilding a SX-780 that belongs to an old friend of mine, and was wondering if anyone might be able to tell me which capacitors can be "safely" replaced on this unit's tuner...

I'm in the process of rebuilding an SX-780 for a friend. He's owned it since new, and one of his STK modules is bad. I will be installing the discrete component modules designed by @rcs16 . I've used them before and think they are a great upgrade. Anyway, in the course of going thru this...

Hello. I've been working to get a Thorens TD-125 back into good working order. After replacing caps, adjusting voltages, getting the motor and platter bearing cleaned up and oiled, cleaning the drive pulley and putting on a new belt, adjusting the suspension and getting a break in the collar...

I have known for years that that the trace side of circuit boards were coated with some sort of lacquer sealant. It always makes a bit of a sticky mess when cleaning old flux off of boards when doing "restoration" work. Other than that, I never gave it much thought until I saw a recent thread...

I am in the process of rebuilding an AU-717, and am now replacing the big filter caps. After jumping around through a bunch of threads, it seems that there are mixed opinions regarding replacement of of the 2.2uf bypass caps in the original Sansui design. Some folks say just leave them out...

Hello all. I'm working on rebuilding the phono board of the aforementioned Sony receiver. It has a pair of 220uf caps, and unfortunately the only 220uf caps I have on hand are too big to fit. I do have some Nichicon UKA 330uf and some Panasonic KZE 270uf caps that will fit, and wanted to find...

Thoughts? :)

I recently acquired an AU717 in non-working condition. I suspect that this project is going to be a long slog. I plan to "restore" it, using Leestereo's restoration thread for guidance. I usually try to address major operating problems before starting on restoration work, but troubleshooting...

I debated putting this in the Turntable forum, but as its really a power supply question, I thought it might be better here. An acquaintance who knows I like to tinker with old audio gear asked if I could get his first system - bought with grass-mowing money when he was a teenager - back into...

I am doing some updates on a Hitachi SR-904 receiver, which is a Class G design. In addition to the two 6800uf filter caps for the primary power supply, it has a dual capacitor for the secondary power rails, rated at 5600uf (x2). There is enough room in the bracket by which this cap is mounted...

I am working to get a Hitachi SR-904 back into good working order. This unit does not have adjustment pots for DC offset. As is, offset is around 45mV in one channel and around 65mV in the other. While these are not too bad, it would be nice to get them closer to the ideal of 0mV. The...