Relay not clicking/engaging in a Marantz 2325

[angelaudio]

Keep R721 out for now.
Test H706 emitter to collector out of circuit, but also when you pull it out to test can you measure the resistance from the H706 solder pads from the emitter to collector to check for a board short.
C712 is out of tolerance, but not a short so it probably needs to be changed, but not the cause of the 60v.
I still can't figure out why the voltage divider network that connects the +60v to -60v does not have the correct voltage at the middle? It should be close to 0v?
Maybe do a quick resistance check in circuit. Compare measured R of R724 (560 Ohm) compared to R725 (560 Ohm) and R722 (27K) to R723 (27K). Or compare with your good deck.
View attachment 3287846

R724: 565ohms
R725: 566ohms
R722: 26.73kOhms
R723: 26.88kOhms

 

[dankik]

That's good. So why don't the voltage drops match what I calculated?

 

[rBuckner]

Because some semiconductor is screwed up that's connected to these nodes? I can tell you my two rules about amp troubleshooting and a bonus third!:

Check ALL semis at once, transistors and diodes, in place if you can. Some low resistances can screw that up though.
Check all power resistors, anything about the standard carbon film 1/2W ones.

A third one is to check for continuity pad to pad, seeing where a trace connects the two pads. A hairline crack, usually at the place where a trace meets the pad can be hard to see and find.

 

[angelaudio]

I’ll check again for hairline cracks with my magnifying glasses.

 

[angelaudio]

Hey guys please excuse my prolonged absence from this thread, I have been a bit busy with work but I am still very determined to get this issue fixed. I have ordered the kit from eatpoint’s online store and will be getting it hopefully by this weekend. I have a nice new hakko that I am eager to use on this project too, check it out:



Working on this P700 board made me realize that a solder sucker just wasn’t going to cut it anymore, hence the upgrade. I also wanted to let you guys know I’m getting a little more familiar with my Tektronix 2246 so I can try and use it to troubleshoot as well if the need arises or if it is preferred in certain situations.

 

[dankik]

Nice! I have one just like it. I also bought a Hakko stand so I don't melt anything with the hot tip. Just make sure that you clean the tip every time when you are done with the two cleaning tools. It also uses small filters that absorbs the smoke that need to be changed after a while. It comes with a few, but you can buy more.

 

[angelaudio]

I just got the kit in the mail today. Unfortunately it only includes 5 replacement transistors and none of them are the ones we narrowed the problem down to previously. The replacements are KSA992 for H701/702/703/711/712. I’ll have to order H704/705/706 from mouser and wait for them to come in.

 

[angelaudio]

Are MJE15032/MJE15033 proper substitutes for 2SC1669(H708)/2SA839(H709)?

For 2SC945(H710/713) should I use KSC2383 or KSC945CYTA?

For 2SA720(H704)/2SC1318(H705) can I use KSA1013YTA/KSC2383YTA?

And for 2SA818(H706)/2SC1628(H707)can I use KSA1381/KSC3503?

I’m uncertain which parameters of these types of transistors are most important to look for when choosing modern equivalents.

 

[dankik]

In case you didn't know, there is a transistor substitution guide on AK here:
https://audiokarma.org/forums/index.php?threads/marantz-transistor-diode-trimmer-sub-guide.926805/
I have highlighted the transistors you asked about.
When you order, please pay attention to the suffix letters as sometimes they indicate a different lead configuration.
I typically look for hfe (gain), Ic, and Vce, package type and lead configuration.
Others could chime-in on what to look for, but usually this guide is put together from other AK's experience and tests.
Please order them from a reputable source like Mouser or Digikey, generally not eB.




Also this post for the 2SC945:

 

[angelaudio]

In case you didn't know, there is a transistor substitution guide on AK here:
https://audiokarma.org/forums/index.php?threads/marantz-transistor-diode-trimmer-sub-guide.926805/
I have highlighted the transistors you asked about.
When you order, please pay attention to the suffix letters as sometimes they indicate a different lead configuration.
I typically look for hfe (gain), Ic, and Vce, package type and lead configuration.
Others could chime-in on what to look for, but usually this guide is put together from other AK's experience and tests.
Please order them from a reputable source like Mouser or Digikey, generally not eB.

View attachment 3292618
View attachment 3292619
View attachment 3292643
Also this post for the 2SC945:
View attachment 3292624

Thank you dankik! Ordered all the parts…except for one transistor that was back ordered (will be receiving that one next month)!

So now I can get to work. I believe you had recommended changing H705 first and then taking measurements. I ordered a replacement ceramic dic cap for that one that was out-of-spec so I’ll do that first.

 

[angelaudio]

Looks like you actually recommended replacing H707 first so I got KSC3503DSTU and its legs from left to right are ECB whereas the old 2SC1628 is EBC so I’ll have to cross the C&B legs. I’ll do that tonight and post readings after doing so.

 

[dankik]

Insulate crossed leads with heat shrink tubing or stripped off wire insulation to prevent shorts. Glad that you caught that!

 

[angelaudio]

I can barely contain my excitement right now dankik. Great news. I replaced H707 and I’m now getting .03V at J809. I won’t celebrate just yet but man am I happy that 60V is gone!

I also replaced C712(100pf 500V) and the 10kuf 80V filter caps before replacing H707 because one of them was physically leaking. Safe to say we’re on the right track and for the first time I have breathed a big sigh of relief. There’s still much work to be done of course but it feels good to know that we’re on the right track! Should I take readings at all the legs of the transistors as you had me do before?

 

[angelaudio]

Jumped the relay and I am happy to report that I got audio through the headphone jack! Bob Marley’s ‘jamming’ never sounded so good

 

[dankik]

Go ahead and measure the transistor voltages and see if they are close to what they should be. Good job!

 

[angelaudio]

Go ahead and measure the transistor voltages and see if they are close to what they should be. Good job!

Will do! I’ll get to it in the morning. I’ve had a long day and don’t want to have my probe slip accidentally and short something. But thank you. Could not have gotten this far without your guidance. Thank you for being patient with me. I’ll have those readings tomorrow morning

 

[angelaudio]

Here are the new readings I obtained after replacing H707 with a new KSC3503DSTU:

H701 E= 1.3 B= .662 C= -20.55
H702 E= 1.28 B= .717 C=-19.58
H703 E= 18.3 B= 17.67 C= 1.27
H704 E= 16.39 B= 15.79 C= -.12
H705 E= -20.2 B= -19.6 C= -.078
H706 E= 44.6 B= 43.9 C= .76
H707 E= -44.5 B= -43.8 C= -.5
H708 E= .781 B= .194 C= 44.61
H709 E= .039 B= -.541 C= -44.6
H712 E= .786 B= .90 C= .16
H713 E= -.469 B= -.323 C= .156
H715 E= -.476 B= .131 C= .785

J702=.147
J703=.001
J704= -45.06
J705= -45.06
J706= 45.06
J707= 45.06
J708= .166
J709= 44.42

 

[dankik]

Thanks. I compared your readings to the old set and most of them have improved to the correct value... with the exception of H003/H004 base. It looks like it should be -59.4v and you measure 0v???
Can you double check the voltage at J703? It traces back to H709 collector, which you measured at -44.6v, but at J703 you measured near 0v (0.001v). Either a bad trace or measurement error.

 

[angelaudio]

Oops my mistake. I don’t think I had my lead on there correctly for some odd reason. There is in fact -44.79V on J703

 

[angelaudio]

By the way I jumped the relay from J809 to J811 and got sound from my test speaker, but it’s coming out of the right channel. This whole time I thought J809 was the Left channel but it’s actually the right channel.