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Platinum repeatably blows speaker fuse in right speaker only

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carvergroupie

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Post Tue Nov 25, 2003 4:34 pm

Platinum repeatably blows speaker fuse in right speaker only

MDX 4 slo blo speaker fuse repeatably blows in the right platinum speaker. Left Platinum never blows. Cannot open fuse holder to check type of fuse in left Platinum (screwdriver slot stripped by previous owner). Platinum serial number is 2456. Please help me troubleshoot. Bought speaker service manual from Vintage Audio Manual few weeks ago. It is copyright 1990 and shows Engineering Change Orders for Model ALS Platinum Crossover Assembly up to and including ECO# 1142 Date 6/26/89. But don't know if manual is appropriate for serial number 2456. Input terminal is not bi-amp type on my Platinums. Service manual shows only bi-amp crossover schematic for Platinums. Manual shows non-bi-amp input on schematic for original ALS. Manual also shows only non-bi-amp terminal cup on the original ALSs. And manual shows only bi-amp terminal cup on Platinums. Are my crossovers from the original ALS design? Have not opened up speakers yet. Requesting guidance before I do. Would also like to convert to bi-amp while they are open (in preparation for hopefully someday Sunfire Signature amp). What should ohmmeter read at the input on back panel (next to fuseholder)? What should crossover components read during individual ohmmeter checks, hopefully without disconnecting components? What other troubleshooting can I do? If components checkout, would converting to bi-amp, which allows an MDX 4 fuse dedicated to woofers and an MDX 4 fuse dedicated to ribbon, potentially solve fuse blowing problem when connecting right channel amplifier output across both inputs? (Still wouldn't solve only the right Platinum blowing fuse mystery until I find out what fuse is in the left) (Amp is Carver 1.0t not bridged). Manual lists MDQ-4 fuse for Platinums. Only have access to MDX-4 and MDL-4. What is the difference? Voltage rating? So far been blowing MDX-4. Not sure if I've used MDL-4 yet. Just noticed manual lists MDL-4 for original ALS crossover. I'll definitely try MDL-4 tonight if I can finish Honey do list. On a separate note, would replacing the crossovers with Platinum Mark IV crossovers improve sound? Are the Mark IVs the latest Platinum crossovers? If not, what is? I've been seeing web sites discussing crossover upgrades. What is really worthwhile doing? Thanks for reading all this. Look forward to the help.
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carvergroupie

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Post Fri Nov 28, 2003 12:56 pm

MDL 4 Fuse blows also

Looked in my bag of blown fuses and found a blown MDL 4. Blown another MDL 4 since then. So, whether the fuse is MDX 4 or MDL 4 doesn't seem to matter in this situation. Spoke with an Apogee ribbon repair person recently and he suggested I may have a blown capacitor. Been seeing on the Internet discussions of replacing capacitors with 400V ones. Service Manual lists 100V capacitors in the ALS crossover and 100V and 150V capacitors in the Platinum crossover. 100V and 150V caps do sound a little marginal given the maximum supply rail voltage on my 1.0t amp (80V, 125V? can't remember, don't have schematic with me), although I don't know how much the crossover caps see of the rail volts. Thanks for reading. Look forward to any advice.
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F1nut

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Post Sat Nov 29, 2003 2:34 am

I think you can safely rule out the fuse being the problem. Do you have the ability to change crossover components yourself? If not, the best thing for you to do is take the speaker in for service. If the service center upgrades anything at all on the one crossover, then you must do the other one too.

As for which model you have. All Platinum models that I know of have bi-amp/bi-wire binding posts with a seperate fuse for the ribbon and the woofers. Do your speakers have one 60" ribbon or two 30" ribbons? It sounds to me like you probably have the original Amazings.
Political Correctness...defined

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In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."
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carvergroupie

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Post Mon Dec 01, 2003 4:48 pm

Thanks for the reply:) I bought these "Platinums" used in 1996. They are finished in the "Black Piano Lacquer" and each have one continuous 60" ribbon. They might be the 1st year for the Platinums and so still have the ALS single inputs (and crossover?). They might also be ALSs upgraded to continuous 60" -- I've heard of that happening. I think, though, I remember (1987/8?) seeing the ALS's finished in some grey resembling the finish on my 1.0t amp. But you do have me wondering what they really are. I think I can replace crossover components myself -- probably too dangerous with an amp, etc. Haven't done any troubleshooting, soldering, etc, in years--busy raising 3 kids. Just upgraded my beat-up 20W soldering pencil iron to a 20W/40W selectable pencil from Radio Shack. Is 40W enough? Also bought Radio Shack's $69.95 multimeter, which is hopefully good enough to troubleshoot a crossover. (I also want to teach my 11 year old son what little I remember of electronics with my 35 yr old Radio Shack 50-in-1 electronic kit.) Any guidance where to go from here? If a capacitor(s) is/are blown, what should I replace them with? Can I bi-amp these xovers? Thanks again for replying.
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F1nut

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Post Mon Dec 01, 2003 5:38 pm

I'm thinking you have the upgraded original Amazings.

It would be a good idea for you to get the schematics before you start in on the crossovers. The Carver ALS Service Manual can be obtained from contacting mike@vintageaudiomanuals.com. It covers the Original, Silver and Platinum models. Also, it will show what needs to be done to upgrade to bi-wire/bi-amp status.

If you need a new capacitor(s) try Michael Percy Audio at mpercy@pacbell.net. Remember that if you change parts (values) on one board you'll have to do the other one too. The 40w soldering iron should be fine.

Keep us posted.

F1
Political Correctness...defined

A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.



In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."
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carvergroupie

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Post Fri Dec 05, 2003 3:05 pm

Thanks.
I think you're probably right about them being upgraded ALSs.
I'll know when I open them I guess.
What constitutes the upgrade besides replacing the two 30 inch ribbons with a 60 inch ribbon? Was anything changed in the crossover?

I have a copy of the service manual from Vintage Audio.
It doesn't seem to address the ALS upgrade.
It is copyrighted 1990 and all the dates seem to stop at 1989.

Dave Sauter's repair site says the ALSs were built through 1988 and the Silvers and Platinums were built through 1993.
Are the Mark IVs the latest Platinums and are they covered by this 1990 manual?

As for bi-amping an ALS crossover, it seems I can't just simply disconnect C1 from R6 and L3 without changing the reactive impedance of the woofer and ribbon sections, otherwise the Platinum crossover wouldn't look so different. Obviously, I only understand circuits enough to be dangerous. That's why I'm looking for some hand holding. I remember Carver claiming the input impedance is 4 ohms resistive in the ALS and 8 ohms resistive in the Platinums, but I also read tests where the impedance (Platinum I think, but maybe ALS) actually varied I think from 2 ohms to 11 ohms across the frequency response.

Thanks for reading. Look forward to your response.
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F1nut

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Post Fri Dec 05, 2003 6:34 pm

To my knowledge, Carver didn't do the upgrades....it was done by the owners or their hifi shop techs, so it wouldn't be in the manual save for the fact that they show the different crossovers. I would think that the crossovers would have had to been changed to the Platinum verison to work with the 60" ribbon.

Take a look at your crossovers, compare them to the ones in the manual and see which one matches up. Report back which crossover you have.

The Mark IV's are not in the manual.

As to the ohm ratings, the ratings are for the nominal figure. All speakers will vary across the frequency response.
Political Correctness...defined

A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.



In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."
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Spollo3

Post Sat Dec 06, 2003 5:32 pm

Amazing fuse/crossover/single post

Hi

I too have a pair of the Amazing's with single posts. It has confused me because the manual indicates bi-amp. I bought last year and immediately had problems with the right speaker. Thought it was the ribbon, but with help from Repair Dave I found 4.6 Ohms resistance. The discolored crossover coil and 25 amp (!!) fuse the moron had in it suggested fried a crossover.

After weeks of searching the Internet for someone to repair them - no one would touch them for some reason - Mark at Meniscus Audio Group reluctantly agreed and rebuilt both with new capacitors and coils.

The resulting sound is stunning. My new Rotel system lead by the RB-1090 amp brings tears to my eyes when those Amazing Carver's respond with life-like, unbelievable sound.

All of the effort was worth it. I have had several problems, however I have been able to fix each one, including taking the ribbons apart one time to connect then terminal that had developed a hair-line crack.

I too know little more than enough to get me in trouble, but each time a problem has developed the volt/ohm meter was my troubleshooting friend.

Scott
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F1nut

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SILVER-7 TUBE AMP

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Post Sat Dec 06, 2003 6:32 pm

Scott,

Hey, sounds great...glad you're enjoying them.

If you think Mark at Meniscus Audio Group would like more business post his email here.
Political Correctness...defined

A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.



In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."
<<

Spollo3

Post Sat Dec 06, 2003 7:19 pm

Crossover Rebuild

I want to emphasize how difficult it was to find someone willing to rebuild my crossovers. For some reason once I said "Carver speakers" I got "no" as the response. I have since studied a little and may eventually make my own.

Mark was a gem. I sheepishly admit I got impatient with him a week or so after not hearing from him, so when I received the crossovers along with his bill I felt like CRAP! He clearly is not in business to hose people.

Mark was profoundly helpful and agreed to check out the crossover components, only charging for repairs to be undertaken. He remained calm in spite of my inquiries for their status, as I was eager to hook them up to my then-new Rotel system. Shipping UPS was about $30.

Info: Meniscus Audio Group, Inc.
4669 S. Division Avenue
Grand Rapids, MI 49548
fax: 616.534.7676
info@meniscusaudio.com
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Spollo3

Post Sat Dec 06, 2003 7:39 pm

Crossover Repair Follow-up

One interesting point to note. I purchased the Amazing's via ebay, driving 5hrs round trip to Portland to pick them up. They looked good but would not allow any volume before kicking out the amp. I could hear sound from all drivers, so the amp "problem" seemed plausible.

Long story short, my Nikko 480 triggered too, so I knew I had speaker problems. I contacted the seller who agreed to buy them back or pay for the repair - he was honorable. However, in my research I realized I had some fine speakers if I ever got them running so I wasn't ready to give up yet.

In the end I only asked for $50 from the seller as his share of the repair. I was so happy with the speakers and outcome, including his honor, I was good with that amount. He was SO happy he sent 4-1/2 times that amount for my troubles! Without consideration for my time, I'm into these babies about $800!!!! Some of the best money I've ever spent.

I live alone in my 2,500 ftsq house, so I tend to run the Rotel-driven Carver's at high volumes which they handle well. I also run a pair of RTR's with my Nikko amp, both fed by a Rotel RC-1090 pre-amp resulting one of the greatest sounding systems I have ever heard!

I buy lots of fuses though. It's a fine line between what the speakers will tolerate and what my Rotel will give them. With one of Monster's better power conditioners I am able to tell when I'm pushing 7-8 amps, which seems to be all I can do before fuses blow in all four speakers. I'm running a lot of power at that point so I really could not handle more volume anyway.

Good luck
Scott
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carvergroupie

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Joined: Mon Nov 24, 2003 11:52 am

Post Tue Dec 09, 2003 2:59 pm

Thanks for all the help so far.

I'm getting braver by the moment.

It is somehow comforting to know there are other fuse blowers and confused single posts out there.

I saw some black ALSs on ebay recently with the two 30 inch ribbons. So much for my remembering ALSs being grey like my 1.0t amp. The case continues to build for my "Platinums" originally being ALSs.

I'll report back on my crossovers as soon as I can remove the grills.

The holidays are slowing me down now. Lots of honey-do stuff.

I should be able to sneak in at least input resistance checks while fixing my wife's lighted yard wiry reindeers. But being caught with speaker grills scattered across the basement right now is another matter.

It is good to know Mark is apparently available as a fallback; it appears he's willing to take on another carver groupie:)

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