Marantz 2265B Repair Part 1
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- čas přidán 30. 08. 2022
- In this video I take on a receiver that's completely dead. Part 1 details the repairs necessary to get the output stage repaired.
#amplifierrepair #electronic #audio #electronicrepair #vintageaudio
Wow, this chassis is amazingly similar to the 2330B I'm working on. What I have found is that with this particular vintage of Marantz, as you said, if you blow an output, it takes a bunch of stuff behind it. Furthermore, knowing what I know now, I would opt for the, "TV shop repair" because the traces on this board are so fragile! Even if you have a good desoldering station and don't overheat it, it doesn't take much for the pads to lift up. Of course, with the transistors, you have no choice. But, even then, you end up bending the leads of the driver or pre-drivers over to get them to make contact with the trace. Lastly, due to the fragility of the traces, you end up with a bunch of bodge wires because the traces are not much more robust than a fuse on this series! I decided to start all over and an after-market replacement board from and ebay seller. From what I can tell, it's far more robust, the traces and pads are silver rather than thin copper-clad. I have the board about 40% repopulated with new parts. I'm looking forward to getting it in and fired up.
Yeah, 40-50 year old PCB's are really delicate. The adhesive that bound the copper foil to the board hadn't aged well, but I doubt the manufacturer ever envisioned these receivers being worked on all these years later!
So interesting, so much learned today. Thank you Ray. I am still on my learning path so the minutia you indulge in truly helps to bring all that knowledge and understanding into context. Thank you so much Ray!!
It's my pleasure, Alex. It really is all about giving back.
Love your comment about just replacing what is bad visually. Something had to cause those visually bad components to go bad. Those visually bad components as you stated were the end result of something else being wrong. Being a parts jockey is not the answer. It is similar to medicine. If one has pains, just do not take a pill to hide the pain, as this is a systemic approach. All one is doing is masking the cause of the pain. Find out what is causing the pain, fix that, and one no longer needs to take pills. Great Job and explanation here!
Thanks Rod! Wish I could find a doctor like you. 😁
@@raygianelli3612Appreciate the reply.. For the record, I am not a Doctor. Was making a correlation. Try seeking out Osteopaths and Homeopaths for Doctors.
Interesting one, Ray. Thanks for the detailed troubleshooting steps and advice.
I'm glad you got something useful from it. That's the whole reason I do these.
Thanks for this video. I'm in the process of rebuilding the P700 board on my 2330B. It's good to see I'm not the only one with errors in the schematics.
I did a 2230B not long ago. Then I got into a 2230 non B version and was surprised how different a design it was. Good luck with it!
I like your videos! -- you are humble when things go wrong and explain how to get back to target! Thank you for all your videos and teachings!
Thanks Brett! Humans make mistakes, and I think it's helpful to show what to do when that happens... and it's going to happen.
This channel is my way of giving back for all the people who took time to explain to me how this stuff works and what to do when it doesn't.
Why doesn't this video have over 1 million views? it should.
Thanks Derek. It's such a niche area of interest that it's never going to be a million view video. Maybe if I added some scantily clad young women it would. 😁
So after removing the two dead transitors on the amp assembly for the FL channel the receiver is working normally missing a FL channel though. I have received the sound matching tubes and wanted to clarify in this video did you say there is almost always something else bad behind a burnt transistor or what it the opposite that it's just going to be the transistor?
@@raygianelli3612
I agree. So much knowledge given here.
Ray, I would like cast my vote for the back to basics videos. All my experience is in telecom, thus I am trying to learn a different aspect of electronics and I ALWAYS glean a nugget from your videos.
Hi Bill!. Thanks for the vote. My day job is in telecom. I'm a central office tech.
@@raygianelli3612 I worked in a SXS/XBAR environment in 1967-1968. When I returned from the Marines, due to injuries, I couldn’t climb poles so they put me on the frame. Later, I transferred back to outside plant. I done installation repair on pay stations and small PBX system’s. I later bid on a job in the test center/repair service bureau. Spent a number of years in that environment and really loved it.
I assume you work on the ESS switches. The PBX systems I sell/service have a lot of commonality with the ESS switches. VOIP is taking over the digital world and it is very frustrating trying to convince the AT&T, Comcast, Verizon, etc, that a trouble is not in my PBX. I honestly think the very first lesson they are taught is, “tell the customer the problem is on the PBX”. I had an issue with a tech this morning. He didn’t even know how to test if ringing voltage was coming through on a line, which it wasn’t.
@@bill_p2074 Wow. I started far later. I had heard of crossbar and step by step switches, but that stuff was long gone by the time I started. Our office had a 1AESS switch, which was cut over about 12 years ago to a DMS node remoted from a nearby office. Office I'm in now has a Lucent 5ESS. Our offices are now 4 walled, so we do it all from frame, switch, toll and generator/power. They're getting away from TDM and going into WDM and fast ethernet. Planned on retiring but the horrendous evaporation of my 401(k) made me reconsider. 😩
@@raygianelli3612 I just aged myself, didn’t I? Our first cutover to ESS was a SXS office in Smyrna,Ga in 1972. The PBX systems I install can do TDM, VOIP or a combo of the two. WDM probably wont make it down to customer level anytime soon.
I hope your 401k will turn in your favor.
Great stuff Ray. Your work and the way you present it is so informative and educational, even for the electronically unskilled such as myself. Looking forward to "Part 2".
Thanks Ian! I'm thinking about doing some "Back to Basics" videos. Would that be of any interest to you?
@@raygianelli3612 You betcha Ray.
@@raygianelli3612 It would to me Ray. Your advice on the transistors and how to read base, collector, emitter was great. Today, while watching your video … actually you do this almost every time, you show us the schematic but today - I don't know what it was but as you explained I began to understand how the electrons move toward the outputs. It's crazy because it's like yes of course, where else would electrons flow? Forgive me because it is sort of funny to have said that but it is true. I think it dawned on me as such is due to not understanding enough yet. Wait a sec? Don't you have a Patreon page yet? I don't need any sneak peek or insider videos but I would like to send something every month, even if it is just gestural in nature. Your productions take a lot of time to put together and I am happy to support you. Let us know. :)
@@raygianelli3612 Such a series would definitely be incredibly beneficial & interesting !!
Your channel should be wayyyyyy bigger. It will be. You just popped on my feed a few weeks ago for the first time!!!! Great and educational big time!!!!
Thanks! Maybe if I worked on search engine optimization it would be, but I'm content to get the message out there and let it grow as it will. It's the sharing of knowledge given to me that drives me to do this.
@@raygianelli3612 maybe you could talk in a video or post what audio forums you really like. Your trick with the multi bags for screws and such is a great tip. !!
good work love how you trace back the destruction-i learned the hard way trying to fault find running live and taking voltage measurements i soon learned its easyer to cold test all the semi,s .on a rebuild like this i would go the whole hog and change the input long tail pair aswell just because how often they go noisy and dc bias drifty in old kit like this , i hate doing a major rebuild just to have it come back with intermittent stuck in protect mode , the dreaded "its gone again" and you know they wont believe you its for a completely different reason , the customer sees the same symptom so they think you messed up, yea ive got a negative tilt ha. oh the tv repair guys jibe ....yea you are right- i had no idea on bigger amps and pa you had to replace parrellel sets of outputs all together with the same batch code if just one failed ....for decades ooops.
Darren, good call on all of the above. I do the differential pairs now, as the transistors used tend to get noisy with age. And yeah, did a lot of sound reinforcement repair work, replacing all the outputs gets real pricy real fast! I try to match them up with the curve tracer. Crown used to sell matched sets, don't know if they still do.
I hear you, my first repair, somewhere in the 80s, was an amp from my father, I could buy him a new one, the hard way, like you said 😅
Great video!
Thanks Keith! The fun never stops with this old stuff. 😁
great info
Always reason, your right
👍 Good stuff
Thanks Joseph. Good to see you here!
Could you remind folks in your next video on what type of electronic design this amp features, I think you said that it is a "coupled" amp? I know that NAD used/uses this design as well for their power envelope (PE) series. They too can see 'catastrophic' like failures in that the design can experience a cascade of failed/burned/blown parts when a key component decides it's time to pack up and go. I recognize that here there were other forces that may have lead to problems such as the 'TV repair', not ideal transistors, etc but if the coupled amps are prone to a more colorful demise let us know because I think it may be interesting to get your take on the amp design aspect. It could be of interest, I don't know.
Alex, this and most amps from the mid 70's up are known as direct coupled. Older amplifiers had each stage isolated by capacitors or small transformers. By designing amplifiers that didn't isolate each stage, a purer signal path was realized. The only downside is that when something lets go it upsets every voltage in the amp, making troubleshooting more difficult.
Nice job as always, loved the TV Repair shop.. Ohhhhhhhhhhh, how I Love a tin foil fuse. Do you use the "Chrome Polish" on front face plates ? Damn, never seen a capacitor expand so greatly it sheds it skin.
It’s weird the guitar amp people say don’t replace my caps, the audio people say recap. I replace as many caps as possible in guitar amps. Sometimes they never ask, all parts are in a bag for them to see, some never notice unless they remove the back. I then explain how their problems came about. One group says one thing an another the opposite.
I think what Ray was suggesting is that caps are not the end all be all of repairs. Of course, when caps get really old they should be replaced but I do believe Ray is coming at us with repairs from the troubleshooting angle. Namely, fix the problem first and then consider any further restoration steps that could help improve the longevity or other attributes that may improve the functional values. I might have misunderstood your comment, for which I do apologize but I thought I would, nonetheless leave you with my two cents worth. :)
If you think audio people are OCD, guitar players make them look like amateurs. The pinnacle of technology was reached for many of them in the 1950's.
@@raygianelli3612 so true every time it seems an old amp come in I hear the comment don’t change the caps, I like the sound. Never mind the caps are leaky some just plain bad. I change them anyway, an I then hear the reply , oh it sounds so great now what was wrong. Besides the caps, usually a bad tube or ground corroded, or maybe a old socket past it’s day. Transistor amps problems are some what different, but caps are always a problem. Most companies don’t use quality parts or ones that should be of better quality. I could cure a great deal of problems in new amps with just using better made caps. We are talking about a few pennies in most cases. I plan on posting a sign that says Don’t Change the Caps They Sound Good…… lol.
Wow, that cool fin, looks like there is something that went very hot. Or the cooling compound missing or burned as well. If you see on the right, something else got hot too. Never seen that before. Or yes, I've seen a Kenwood amp, that was burned the PCB on the supply side, carbonized every thing. I told the owner that this was the end of the ride, seems they used the amp, when it was raining. Must have been a serious crash.
Used when it was raining? Unbelievable!
@@raygianelli3612 My former boss, was very neglecting for his material, so I guess, this one was used in outdoor event, what we did very often with the radio station. So I earned good money with his "mistakes" I have pictures of the poor thing. But I'm not an expert in repairing burned PCBs, and in work hours it would be very expensive, so that kind of repairs are most for the recycle. It's sad, because that Kenwood KR4030 was a pretty thing. Now I'm troubleshooting my own technics_su-x102_sm_1, which, with starting up, gives a spike. Not healthy for your speakers.
What do you think causes R726 (the 300ohm) to keep smoking? I’m dealing with that right now and keeping the outputs out of the equation until I can isolate this. All transistors in the bad channel are replaced and no longer shorting. These seem to have common issues (the 2265B in particular)
Hi again Ray, hope you’re in good health & good spirits. Thanks as always for such a thorough tutorial. I’ve got a few questions about certain steps of the process, so if at some point you have a chance to answer some or all of them, I’d be incredibly grateful.
1. @ 2:40 , when you said it’s not coming out of protection, did you determine this b/c you didn’t hear the protection relay click ?
2. @ 3:35 you measure the emitter resistor’s dc voltage relative to ground. For determining dc offset , would it not be more accurate to measure for vdc across the resistor ?
3. @ 3:55 was it the coupling capacitors whose voltage you measured relative to ground to check how much vdc the output end of the PS was putting out?
4. @ 8:15 did you know which transistor was PNP in which NPN based on visual cues? Or just from having seen those transistors in the past?
5. @ 12:15 you said that with such direct coupled amps, it’s not uncommon to have shorted transistors & resistors going all the way back to the preamp stage, & as you discovered later in the video, that turned out to be exactly the case with this amp too. But if you have shorted output transistors in a capacitor coupled or transformer coupled amp, in your experience, do the coupling caps & transformers normally serve as a good barrier to prevent the short from reaching components back in the driver or preamp stage?
6. @ 13:45 you check the driver transistors in the circuit, but earlier you check the output transistors out of circuit. Are both in and out of circuit tests acceptable for any amp transistor?
7. @ 24:50 you said you went to night school for 1.5 years. Was this for a course specifically about amplifier repair, or a general electronics repair course?
8. @ 25:45 if I’m unsure whether the replacement transistors have the correct bias for my particular amp pre-set at the factory, is it ALWAYS acceptable to just turn the bias on the scope all the way down (when it’s time to test the repair) like you did?
9. @ 26:25 how did you immediately determine that the power cord is faulty, without first putting it through a continuity test?
Whew! OK:
1. Yes, I listened for the relay click. Some gear has a light or other visual indication that it's out of protection. This one does not.
2. No, because the unit is in protection, the relay is open. Therefore you would measure zero volts across the resistor, as no current could flow through it. When you measure DC offset, you're usually instructed to measure the speaker terminals (which is the amplifier output and chassis ground), which we can't do when it's in protection.
You may be confusing bias setting with DC offset.
3. Those are the power supply filter capacitors. There are no large coupling capacitors in direct coupled amps.
4. Yes. Japanese transistors with the prefix 2SA and 2SB (often the 2 is omitted) are PNP. 2SC and 2SD are NPN. Wish all semiconductors were like that!
5. If you use the term "capacitor coupled amp" to most, it indicates that the output is capacitor coupled (or transformer, like McIntosh, which is actually an autoformer). Amplifiers that utilized capacitive or transformer interstage coupling went out in the late sixties. The exception of course would be tube amps.
So, yes, in a mid sixties to very early 70's amp, the damage would be limited by caps or transformers
6. In circuit testing .can point you in the right direction, but out of circuit is definitive. There can be parallel current paths in circuit that can skew your measurements, but shorted is shorted.
7. Strictly a vocational electronics course, which probably no longer exists today.
8. The scope has no bias. When the output transistors are replaced, it's good practice to turn the bias to zero, then set it after warmup. Bias is the small current that always flows in an output stage, and while today's transistors are very consistent in manufacture, it doesn't take much variance to change the bias. I did a video on offset and bias that explains much of this.
9. I should have shown this, but moving the power cord caused the unit to turn on and off.
I don’t know why CZcams deleted my reply from a few days ago , but I hope it doesn’t delete it again . Just want to thank you for being kind enough to take the time & effort to promptly answer all my questions , you’re an absolute diamond Ray ! Many cheers to your health & wealth sir !!
@@bigmedge Thanks for the (very) kind words!
Hi Ray
Enjoyed your troubleshooting. Amazed at the parts damaged. Knew you would find them. Did not know about nec transistor. The transistor you used, how close to original specs were they? Thanks, enjoyed the video
Robert
NTE are aftermarket subs, and the problem is they'll spec a transistor for a variety of transistors. It will therefore work better in some applications than others. I used Onsemi MJ21193/94's for outputs. They exceed every parameter except Ft, which in this case isn't a big deal.
👍
Curious... at the very end when you're increasing the signal voltage (which is what I assume you're doing) to get to the 65W output from the amplifier, where do you have the amplifier volume control set? Is that important or not? Do you generally set the amplifier volume knob at a specific point and then just vary the input amplitude? Thanks Ray!
William, that's a pretty common question. And as you suggested, it really doesn't matter as long as your signal generator has enough output to drive the amp to the edge of clipping.
@@raygianelli3612 thank you sir!
Great trouble shooting. Any thoughts on why the driver transistors would short ?
Very common for the failures to cascade back from the outputs, so it's not unusual for this to happen. Question I have is this: did that failure happen AFTER the fuse was wrapped in tinfoil? Because the failures went back farther than usual.
@@raygianelli3612 So the output shorted first? If so what would cause that, possibly the bias went high? Foil on the fuse surely made things worse.
@@scrappy7571 Common cause of shorted outputs is shorting (even momentarily) the speaker wires, or impedance below what the amp is rated to work in. No way of knowing when the fuse was foil wrapped. 🙃
Did I see .47 Ohm emitter resistors on the other channel?
Good catch, my friend! The one I pulled out was a .33 and I didn't look at the others. They're all supposed to be .47 ohm. Thanks for pointing that out.
hello, there are subtitles everywhere, but there are none here, which makes me sad :-(((
Luke my friend, I hear you. Set up subtitles on all but the newest video. Apparently it takes time before you can add them to a new video.
@@raygianelli3612 thanx ;-)
I have a 2325 for ya ta fix. I got it while I still was in High Skool heh. Junior. Let me fix all the burnt stuff first.
Burnt stuff? Yikes!
Someone tryed to make an Audiophile fuse.
I know you're kidding, but I've seen a vendor selling supposedly "audiophile" fuses for $50 each. This is not something I believe in.
Hope my tech doesn't move my Marantz equipment around sliding all over scratching the top face metal and sides. Wood or no wood. Try a towel 😏
That's a conversation that should be had with your tech.
YOU GOT all the bugs🦟🦗 🪳out. So you get the ***ELECTRONICS REPAIR VIDEO OF THE YEAR AWARD!*** Couldn't have explained any better but you DID forget to lambast the chef that used the aluminum foil, it was not called for in this recipe. Momma Mia! Now put on 120 watts of a Kiss song - Shock Me!
Foil, right? Sheesh!
But it brings up a good point, and that is check the fuse holders for things like that, and even if the fuses look good and measure good, they need to be checked to make sure that the proper value of fuse is installed. Too many times I've found the wrong value of fuse installed, sometimes way too large.
All of this equipment is at the age where it's almost certainly been serviced or molested. :)