My Marantz 2230 Rebuild Thread

Discussion in 'Marantz Audio' started by tensleep, Mar 30, 2017.

  1. tensleep

    tensleep AK Subscriber Subscriber

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    Last week, a good friend purchased a very nice example of a Marantz 2230. I had intended to give this to a local technician, but he is busy with his regular job for the next month or two. So, I believe that I will give this a go. I have a good solder station, desoldering tool, a dual trace oscilloscope on the way, a good Fluke 87 DMM, a bench, lots of hand tools, etc. I just finished downloading the manuals/schematic from the database and will create a binder over the weekend.

    I work as an industrial electrician, and have worked on PCB electronics, off and on. Recently, I fixed up a Crate tube guitar amplifier - reflowed solder joints, made some tried and true circuit modifications, all with good success.

    I have also worked on a couple of SS receivers. One, a Sony, is still disassembled from over a year ago - divorce, relocating, etc. I didn't want to get it out until I was sure I was ready to get back into it. Then this Marantz came up.

    My friend found a pair of EV Interface 3 Sentry II speakers, which I have already fixed up. He intends to drive them with the Marantz.

    I will document my progress here over the next couple of weeks. Please feel free to comment, constructively of course. I hope to leave a decent thread for others to follow, complete with pictures and in depth discussion of component choices, as well as any problem solving scenarios encountered.

    Since I have several other receivers that I would like to work on, I have the following questions regarding test gear:

    1. How important is a signal generator?
    2. Is an app sufficient for this purpose?
     
  2. tranguru

    tranguru Active Member

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    Hi,

    does the unit work?

    if it does and you really want to maintain it a bit (if it ain't broke, don't fix it), I would do the following:
    • replace the electro caps
    • clean the contacts with KONTAKT 60 and 61 (very often forgotten)
    • replace light bulbs if needed (watch out for the stereo lamp !) - maybe replace with LED lamps
    • check DC output, on the power amp.
    • check power supply voltages - is they are OK and unit sounds OK , I would stop there
    luck
    Robin
     
  3. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    You shouldn't need a signal generator for a routine rebuild. If it isn't working properly, you might need it for diagnosis. You also need one when finished if you want to test power output. That would involve signal generator, scope, DMM and dummy load. You will find lots of different opinions on how far to go changing components on a working unit. My minimal version would be electrolytic capacitors on the Power supply and power amp boards plus the big filter and coupling caps. But in the end, I usually replace all electrolytics plus a few known troublesome transistors and diodes. On the 2230, you will have two main adjustments to make: Power supply voltage and idle current (bias). Instructions in service manual, but I believe the bias instructions may be incorrect. I have three main pieces of advice:

    1. Use the search function near the top right of each page and search for all of the 2230 related rebuild threads you can find. Study them and you will learn many of the pitfalls ahead of time.
    2. Scan all pages of the Marantz Service Manual Error Thread (Near top of Marantz section of the forum) for any references to the 2230. . It will save you much trouble.
    3. Before you start, build a Dim Bulb Tester and use it every time you power up for the first time after working on the unit. It could save your bacon if you have a short somewhere. Here is a great thread with DBT build instructions.
    Good luck!
    Steve

    http://www.audiokarma.org/forums/index.php?threads/compact-dim-bulb-tester-wiring.465423/
     
    Last edited: Mar 31, 2017
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  4. tranguru

    tranguru Active Member

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    Hi Steve,

    what would the "a few known troublesome transistors and diodes".
    do you a kind of list per unit?

    Thanks
    Robin
     
  5. hirscwi

    hirscwi AK Subscriber Subscriber

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    The SC458 transistors on the phono PCB - replace with KSC1845 gain code "F"
    The VD1212 diode on the phono PCB - replace with 2 1n4448 in series or 2 1n4148 in series
    The VD1122 diodes on the phono PCB - replace with a single 1n4148or 1n4448 diode

    Also not a bad idea to replace the S1B-01-02 diodes on the PSU with UF4005. These don't fail but the replacements may lower noise floor.

    If you want a list of the generally accepted replacement sizes, please feel free to start a conversation.
     
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  6. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    I'm no expert, but I've spent a lot of time studying the threads and working on many 22xx units. The consensus seems to be that any 2SC458 transistors should be replaced. Apparently they are very prone to develop noise. Most of these units have at least a couple of them. On the power supply and phono board, I always replace the non-zener diodes -- mainly because it's easy and the parts are readily available. I will PM you a widely used complete parts list for the 2230. I didn't put it together, but I have used it for two complete rebuilds, and the units sounded great afterward. But if you just wanted to work on the PS and amps, you can pick those off the list. Note that the big cap replacements on these are significantly higher capacitance rated than the originals. There seems to be some controversy about whether that is wise or not, but it worked out fine for me. Here is the recent thread where several of the experts have a throw-down over the issue. I have great respect for the guys who think the higher cap ratings are a good idea and those who don't, so it's your decision on that.
    Steve

    http://audiokarma.org/forums/index.php?threads/effect-of-coupling-capacitor-sizing-on-a-2230.763730/
     
    Last edited: Mar 31, 2017
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  7. tensleep

    tensleep AK Subscriber Subscriber

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    Thanks for the replies, support and suggestions - that is what I want. Especially parts numbers and known issues to look for.

    I do have a variac and a load center wired - gotta dig it out - with a terminal strip for a dim bulb. I need to get a socket from the hardware store. I will post pictures over the weekend as I set up my bench and power on the 2230. Stay tuned and keep the replies coming.

    I did read through the coupling capacitor thread last night, prior to posting, and understand both sides of the debate. I also tend to be a bit conservative when it comes to modifications, but have been known to make a few from time to time, when it made sense, didn't create an irreversible change and was cost effective. I have also read through most of the rebuild/troubleshooting threads and will continue to do so as I go through this exercise.

    I do need to relamp. My friend said he would probably like the LEDs, because he won't be able to replace the incandescent lamps in the future and he may gift this at some point. He really wants Mac and Ohms.

    My plan is to setup the 2230 on the bench, complete the variac/dim bulb/load center test station and set it up on the bench, then bring up the Marantz, with the cover off, and check the test points. Oh, and print and make the binder for the manuals, schematics, my pictures and notes. This will help me keep things organized and provide documentation for my friend for the future. I should have the binder started and the bench setup finished by tomorrow. It depends on how ambitious I am tonight. I do need to change out a capacitor in my VC5310 guitar tube amp and may try to sneak that in before I get too bogged down in the Marantz.
     
  8. tranguru

    tranguru Active Member

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    you probably know, but just in case: for the LED you need to foresee a small rectifier circuit and current limiting resistor.
    LEDs don't like too much current and certainly no AC across them....
    also stereo lamp - check rating 6.3v 0.04A!! not the 0.2A as for the rest - so an LED should be ok too - would like to the thoughts of the others too

    R
     
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  9. tensleep

    tensleep AK Subscriber Subscriber

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    Thx for the heads up on the LED circuit - I hadn't really planned it out yet. Voltage divider/current limit resistor network, rectifier, and possibly a current limit varistor of some type to provide a dimmer. Perhaps.
     
    Last edited: Mar 31, 2017
  10. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    Actually there are now LED fuse type bulbs that are exact replacements for thr original incandecents and LED replacements for the bi-pin lamps for the input indicators and stereo light. All are drop in. No modifications required. Two sources are AK member dgwojo at dgwojo.com and AK member runningdog at irebuildmarantz.com.
     
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  11. tensleep

    tensleep AK Subscriber Subscriber

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    I wasn't feeling too good last night, so I didn't get anything accomplished. However, I am going to invest some time right now. Quick question - before I spend time researching the Dim Bulb Tester (DBT), it's just a lamp in series with the 120vac power, right?

    Edit: hmm, I think I have an ammeter floating around here somewhere, too.
     
    Last edited: Apr 1, 2017
  12. tensleep

    tensleep AK Subscriber Subscriber

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    Variac, DBT, resistive loads ready for action.
     

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  13. tensleep

    tensleep AK Subscriber Subscriber

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    14910962215161862160036.jpg 1491096253928315315740.jpg It is alive!!!
     
  14. tensleep

    tensleep AK Subscriber Subscriber

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    Both channels work on Aux input with Chromecast Audio, distortion in left channel. Could be a number of problems. No more running it until I get the cover off and make some measurements.
     
  15. disisme

    disisme AK Subscriber Subscriber

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    I'll be following along.
     
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  16. tensleep

    tensleep AK Subscriber Subscriber

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    I took the time to rough in a parts list provided by a fellow AKer (thanks Steven) and, after comparing the costs, I decided to go with the standard Panasonic kit from irebuildmarantz, along with the LED lamp kit. The cost was equivalent, and it took about 2 hours to get a decent BOM and estimate from Mouser. The BOM would have required another couple of hours of tweaking to get the list right. I have had experience creating a project with Mouser before; they are a great resource, but since the legwork was already done, I went the easy route.

    I have used and like the performance of the Panasonic/Wima capacitors before. My friend reiterated that he isn't interested in bleeding edge performance; rather, he wants solid performance with reliability and longevity. This kit is advertised as such. The parts should be here by the end of the week, which will give me plenty of time to do some cleanup/prep work.
     
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  17. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    I have used Randy's kits a couple of times. He provides quality parts, everything you need is there, and he is availabke as a valuable resource if you run into trouble.:thumbsup:
     
  18. tensleep

    tensleep AK Subscriber Subscriber

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    That is good to hear! I really want to do this right the first time.
     
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  19. tensleep

    tensleep AK Subscriber Subscriber

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    My parts should arrive Friday!!!!
     
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  20. tensleep

    tensleep AK Subscriber Subscriber

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    This came in the mail today - woohoo!!!!! I am very happy with my choice - this takes out so much guess work. Randy rocks.

    IMG_20170407_202109.jpg
    image-20170407_202221.jpg
    image-20170407_202435.jpg
    image-20170407_202709.jpg
    image-20170407_202817.jpg
     
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