The case of the possessed Sony TA-N77ES

[Nick89rs]

This amp contains a veritable cornucopia of relays!

The ones dr.audio suggested you check on are RY301 and RY302. Just to clarify, since speaker relays are also being discussed at length, RY301 and RY302 are not speaker relays. RY301 appears to switch between fixed and variable inputs, and RY302 also does something input-ish Meanwhile the speaker relays are RY901 and RY902.

Which relays are the new relays from Germany meant to replace? Best to use schematic designators like RYnnn instead of or in addition to marked-up pics.



There's no bad place to start... It's a complex amp, but the cause of the fault you're experiencing is probably pretty simple. You'll get her fixed! You got this

This amp contains a veritable cornucopia of relays!

The ones dr.audio suggested you check on are RY301 and RY302. Just to clarify, since the speaker relays are also being discussed here, RY301 and RY302 are not speaker relays. RY301 appears to switch between fixed and variable inputs, and RY302 also does something input-ish Meanwhile the speaker relays are RY901 and RY902.

Which relays are the new relays from Germany meant to replace? Best to use schematic designators like RYnnn instead of or in addition to marked-up pics.



There's no bad place to start... It's a complex amp, but the cause of the fault you're experiencing is probably pretty simple. You'll get her fixed! You got this

Noted on using the schematic designators, i will do that, thank you.

The relays purchased from Germany were purchased here: Sony Relays

Embarrassingly i dont know the answer to your question, i assumed a speaker relay was a speaker relay and it said it was for my amp model... i swear ive learned a lot in the weeks since...

the website doesn't give any specs that i can see but there is some nearly impossible to read writing on the new relays themselves seen here.



the part number for RY901 and RY902 is 1-515-676-11 in the service manual. These look to have a similar format/size but i do not know if the specs match.

Im also having trouble understanding how the giant metal covering for the large capacitors comes off and it needs to be removed for me to get at the board those relays are on. It had 6 screws that appeared to be fastening it to the chassis but once they were removed it still wont budge. Im having trouble finding video of anyone doing disassembly in that area of the amp and the service manual seems rather vague.

 

[MFRD]

the part number for RY901 and RY902 is 1-515-676-11 in the service manual. These look to have a similar format/size but i do not know if the specs match.

Relays aren't very hard to match electrically. The tricky part, at least for a PCB relay like this, is that the pin pattern of the relay must match the hole pattern drilled in your PCB, and those aren't always standard. So before ordering PCB relays download the datasheet and ensure the pin pattern is going to match.

The relay in the pic is a pretty common Omron G2R series, probably a G2R-2 DC24 like this based on the use case, but verify. The exact model reference should be printed on the case.

 

[Nick89rs]

Ok, verified the relays were going to work. Had to nip two pins I didn't need off the bottom of them.

Disassembly was harrowing and getting both of the 4 post speaker terminals off that board so I could get to the relay pins was challenging. But here we are, about an hour into playing music and no troubles so far. I think I'm about a week of listening session away from calling this fixed but cautiously optimistic so far!

 

[Nashou66]

Ok, verified the relays were going to work. Had to nip two pins I didn't need off the bottom of them.

Disassembly was harrowing and getting both of the 4 post speaker terminals off that board so I could get to the relay pins was challenging. But here we are, about an hour into playing music and no troubles so far. I think I'm about a week of listening session away from calling this fixed but cautiously optimistic so far!

View attachment 3858464

Hopefully thats it.

You could also open up the relays you removed and look at the contact points to see if they look oxidized where it might hinder a clean signal to go through.

maybe take some close up pics of the old really contact points , just to satisfy mine and possibly others curiosity lol

Athanasios

 

[Nick89rs]

do t know if these look good or bad but here they are.

 

[Nick89rs]

ok its after dinner. i had time to hook up my meter to the relay.

right channel pins with the relay closed: 6ohms and 157ohms

left channel pins with the relay closed: 900K ohms and 1.2M ohms

feels like a winner.

 

[MFRD]

900K ohms and 1.2M ohms is... unusual. Are you sure your probes are making good contact with the pins? Are you using minigrabbers? Usually you would see a few ohms or dozens of ohms across dirty contacts. Anything over 0.1 ohm (after deducting your meter leads' own resistance) is too much and warrants cleaning.

That said, these values would definitely explain why no audio was going to your left speakers, but that fault would more likely be permanent than intermittent.

If you want to try and clean your old relays, first douse the contacts in CRC QD to flush loose grunge, then soak a piece of regular copy paper in Goof Off or whatever strong solvent you have around the house, insert the paper between the contacts, close the contacts by hand and rub the paper back and forth between the contacts. If streaks of dirt appear on the paper, you're on the right track. Keep adding solvent and changing paper until paper comes out clean. Measure again and you should see <0.1 ohm across closed contacts.

Then coat the contacts with Deoxit D5 if you have it, put the covers back on, and save the now-working relays as backups.

 

[Nick89rs]

I'm testing them like this however it's wildly inconsistent. It I really push hard down on the coil contact with my finger I can get it to read a couple thousand ohms but just pressing with a pound or so of force this is the reading.

 

[Nick89rs]

regardless the contacts of both relays are COATED in a black oxide. i hamfistedly destroyed the covers to the old relays dissembling them so no sense in cleaning i suppose unless i just want to see if i can get them back to good for practice.

 

[MFRD]

Don't feel bad, those covers are tough to pop. If you're inclined to fix more vintage gear in the future, then by all means clean your old relays. Practice makes perfect

 

[Nick89rs]

Don't feel bad, those covers are tough to pop. If you're inclined to fix more vintage gear in the future, then by all means clean your old relays. Practice makes perfect

I'm not sure what it was coating those contacts but it was not soot or standard grime. CNC electrical cleaner did nothing to take it off and neither did deoxit on a paper towel. I ended up taking a sheet of fine grit polishing paper and gently cleaning both relays then treating with some deoxit gold and got them to about 1 ohm with the relay shut.

Based on my limited understanding of how this circuit works I'm sort of shocked that the amp was able to put out any sound based on what you all are saying. However it also feels like this really could have been the problem all along and that's hard to understand based on what everyone was saying about the meters reflecting the issue.

Going to use the amp every day this week and if it's drama free through that time I'll update, hand out some very well earned thank yous and appreciation and we will call this goose cooked <3

 

[MFRD]

The black stuff is silver sulfide, the product of the chemical reaction between the silver layer on the contact surface and sulfur from atmospheric pollution.

It's the same stuff that causes the so-called "black leg disease" of vintage transistors and various discrete components.

In relays, the silver sulfide film increases the resistance across the contacts and can cause outright drops when the switched voltage is low, such as with speakers played at polite sound levels.

High voltages can punch right through the sulfide layer and restore contact. Therefore, play your system at maximum volume to keep your speaker relay contacts healthy. This right here is audio's answer to the Italian tuneup

Incidentally, sanding off the sulfide layer also destroys the contacts' outer layer, so while it may temporarily restore functionality the relay should be replaced just like you did. Hope your amp is cured

 

[Nick89rs]

Well....

The left channel is again AWOL.

The failure mode has shifted slightly though. Its no longer going totally dead, and when its dropping out the sound is clean and undistorted instead of a total mess like before, but at very very low volume. So, progress but not fixed.


I cannot get the preamp to power through and bring the channel back (I enjoyed the Italian tuneup comparison) however if i disconnect the RCAs from the preamp and give the left lead a little tap with my finger that always revives it.

Im at a point where im second guessing myself and have reversed the leads on this pre-amp and am waiting for another failure to ensure the left still goes dead even though it had this behavior with another pre-amp and my old pioneer cd player.

i thought i might be onto something yesterday after the left channel died when i hooked up a different set of RCAs i was able to wiggle the input jack and get the channel to turn on and off but i took off the input board again and tripple checked all the connections and visually inspected it with a lot of scruitny and nothing seems amiss there so i think i was just creating line noise that was reviving the channel.

Ive ordered replacements for RY301 and RY302, i found some NOS parts for about 10 dollars each so im going to chase that theory for now.

 

[MFRD]

Have you reflowed your RCA input jacks' solder joints? Not just examine them but reflow them regardless of how they look.

While your soldering iron is hot, you may want to pull and measure R301. Just to check that box

 

[Nick89rs]

Have you reflowed your RCA input jacks' solder joints? Not just examine them but reflow them regardless of how they look.

While your soldering iron is hot, you may want to pull and measure R301. Just to check that box

Yeah, a couple pages back you can see the work. Someone had done work there previously and left a mess. I used the new solder sucker to get all the solder off, cleaned up all the old resin and redid the input jacks completely. It looks nice now.

Will do on R301.