Yamaha newbie A-700 resto thread

[Bratwurst7s]

While I am blabbering about stuff, I do not know how much tolerance we can accept from nominal in a zener before it starts to adversely affect a circuit. That would be a question that someone like Avionic can answer better than I will ever be able to.

I had a really tough time finding the exact ones that I needed for my Denon project, so I ordered a half dozen different ones for each of my different voltages.

This is where the Zen 50 is a really nice tool. It displays the zener voltage, forward voltage drop and resistance. So I was able to use it to quickly get an idea of which of the variants that I bought was in the range that I wanted, and sort through them to find matched pairs for the positions that I needed.

Now, I don't know if a few tenths of a volt difference will make a problem when you have 2 zeners working together for a specific voltage on + and - rails, it might be time better spent drinking beer, but I also figure that you also can not go wrong by matching them.

Cheers,
James

 

[Soundscape]

500mW.

I just wanted our friend Soundscape to get enough to read.
I'm not so sure that you can buy HZ or HZ-L any longer. Mouser doesn't have any.

Cheers,
James

Thanks, I'm getting data sheet headaches dudes. Check out this bullshit! I ordered these and installed them in my A. Ahem, A-1020. The f'ing manufacturer data sheets show the nominal voltage as 5.75 while Digikey shows it as 5.95. Which would be perfect cuz the old pricks are 5.8 - 6.1 , 5.95 nominal jones.
Now I don't know what to believe and my A is full of them now.

https://www.digikey.com/en/products/detail/nexperia-usa-inc/NZX6V2B-133/2119765

 

[Soundscape]

it might be time better spent drinking beer

Amen. My datasheet experience today is sending me right down that liquid road. F

 

[Soundscape]

I couldn't find them. The replacement I have coming today is NZX6V2, with the "B" rating the same 5.8 to 6.1 listed for HZ-6 "C1" in its datasheet.

Same issue with that damn B&C rating. Obsessing over it too much I spose. The ones you ordered are the same ones crammed in my A.

If you got that part # from a local Sensei I'll just crumple these datasheets & crack a brew. F it

 

[Bratwurst7s]

Thanks, I'm getting data sheet headaches dudes. Check out this bullshit! I ordered these and installed them in my A. Ahem, A-1020. The f'ing manufacturer data sheets show the nominal voltage as 5.75 while Digikey shows it as 5.95. Which would be perfect cuz the old pricks are 5.8 - 6.1 , 5.95 nominal jones.
Now I don't know what to believe and my A is full of them now.

https://www.digikey.com/en/products/detail/nexperia-usa-inc/NZX6V2B-133/2119765

This is exactly why I ordered a spread of different parts for the values that I was looking for. The stated info at Mouser etc did not inspire me, so I hedged my bets. At a few € for 100 of each it was cheaper to buy too many parts than make a second order.

The Zen 50 was not cheap, something like €75, but it is the only test device that I could find that will quickly test the zener voltage.

James

 

[Bratwurst7s]

You can use a bench top power supply and a 1k resistor to test a zener, or a 9v battery if the zener is under 9v.

The resistor limits the current I believe, simply put it in series with the zener and connect to the power source, set the psu to a voltage above the zener voltage and use your DMM to measure the voltage drop across the diode.

The Zen 50 is a f#€k of a lot easier.

Cheers,
James

 

[analogwisdom]

You can use a bench top power supply and a 1k resistor to test a zener, or a 9v battery if the zener is under 9v.

The resistor limits the current I believe, simply put it in series with the zener and connect to the power source, set the psu to a voltage above the zener voltage and use your DMM to measure the voltage drop across the diode.

The Zen 50 is a f#€k of a lot easier.

Cheers,
James

The TC-1 can do zener voltage, but who knows how accurate it actually is.

 

[avionic]

What is the OEM part # for the zener in question ?

 

[avionic]

View attachment 3162398

The TC-1 can do zener voltage, but who knows how accurate it actually is.

What is the battery voltage of the TC-1 ? > 25 vdc ? I'd question the accuracy as well.


Most accurate would be bread board a test circuit. And measure the voltage with your Fluke or whatever multimeter your using.

 

[analogwisdom]

What is the OEM part # for the zener in question ?

D108, HZ6C-1L... replacement ordered based off your post from 2015:

HZ6C-1L 5.8v - 6.1v 500mw

Exact replacement...........
http://www.mouser.com/ProductDetail/NXP/NZX6V2B133/?qs=/ha2pyFaduifKOz3qYv/XywIy4M5N7lroz7EpRWUwGk=

You're the man.

 

[analogwisdom]

whatever multimeter your using.

Klein MM325... fairly cheap one from Home Depot

 

[Soundscape]

You can use a bench top power supply and a 1k resistor to test a zener, or a 9v battery if the zener is under 9v.

The resistor limits the current I believe, simply put it in series with the zener and connect to the power source, set the psu to a voltage above the zener voltage and use your DMM to measure the voltage drop across the diode.

The Zen 50 is a f#€k of a lot easier.

Cheers,
James

Thanks Mr. Bratwurst. I just now built your ckt idea with the 9 volt battery jones. Tested 2 zeners in link below with a dead nuts accurate Fluke.
1 was 5.96
2nd was 5.97
Good enough for me
The manufacturers data sheets are dicked up.

https://www.digikey.com/en/products/detail/nexperia-usa-inc/NZX6V2B-133/2119765

 

[analogwisdom]

is the highlighted capacitor for relay startup delay timing?

 

[avionic]

View attachment 3162489
is the highlighted capacitor for relay startup delay timing?

Yes..

 

[analogwisdom]

Yes..

10-4, thank you. Swapping out the KZ I put in that spot for a low-leakage KL...

 

[analogwisdom]

As promised, right channel replacements...

I checked the following by pulling and using the TC1 tester, they all tested OK with that. Not sure how much that's actually worth.

TR104 TR106 TR108 TR110 TR112 TR114 TR116 TR118 TR120 TR122 TR124 TR132 TR134 TR144 TR146 TR147 TR148

And the replaced transistors...

Location (S/M)	Original P/N	Replaced With?
TR126	2SD400	BD13516S
TR128	2SC2705	KSC2383O
TR130	2SA1145	KSA1013Y
TR136	2SC3298	MJE15032G
TR138	2SA1306A	MJE15033G
TR140	2SC3370	2SC3857
TR142	2SA1333	2SA1493

Diodes...

Location (S/M)	Original P/N	Replaced With?
D108	HZ6C-1L	NOT YET
D110	1S1555	NOT YET
D116	1S1555	1N4148

Someone yell at me if you want voltages and I will oblige.

 

[analogwisdom]

Fellas, I replaced the two bad diodes I found last night...



Relay clicked much faster... No more crazy bias jumping...

Been on for 20 minutes, bulb dim as can be...

Offset 0mV at both speaker terminals...

What should I do now?

 

[avionic]

What should I do now?

First Tweek the bias down to nil.. Take it off the bulb and re-bias it..

Then...



See if it works...

 

[analogwisdom]

See if it works...

Well, I plugged it into the wall and sparks started flying...




Just kidding!!! Relay kicked in after about 5 seconds no problem!!! Let it warm up and bias is locked in!



Both channels are in, I didn't take a pic of the 2nd one!

Hooked up speakers and guess what else - BOTH CHANNELS WORK PERFECTLY!! No more mysterious missing channel!!!

All of the inputs are dead quiet, tone controls and loudness work beautifully, balance/volume are smooth and silent, muting is working great... I'm afraid to use class A mode right now. Direct works too but why would I want to bypass all of those WIMAs... lol.

It seems too good to be true, I finally get to use this emoticon!!!

I got zip ties to put on wire bundles, screws to put back in, and just get everything back together but THANK YOU everyone who helped me with this. More pics to come!!!

 

[Soundscape]

Wowzers...congrats!