AMS reverb - is it worth fixing?

Steve Jones

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I have an AMS RMX-16 here that comes up scrambled on power-up. Someone gave it to me a while back, and it has been so long since I recorded with one I can't remember if they would still hold their own against modern units. Clearly the computer is not running. I do know that it will be a tough job though, I have a service manual and some of those parts will be tough to get if there is a problem with RAM or convertors. Perhaps the spares bin may be a better idea, but if anyone is familiar with them it would help to know the common faults with these units.
 

pan

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Nah, this is not worth the hassle - send it over to me, I will cover your shipping expenses...
















...lucky bastard! :thumb:

Most problems I noticed our tech having with the AMS units are RAM and heat related - sorry for this unprofessional advice.

n
 

gyraf

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Congrats on the catch!

Try removing and cleaning the edge connectors for the subboards. Change the reservoir electrolytic capacitors in the powersupply. Do a reset.

If it's something digitally-electronic gone wrong, these are VERY hard to repair - as all AMS stuff.

Jakob E.
 

Steve Jones

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I don't know about lucky, it looks like AMS and Lexicon must have had a competition to see who could build the most unreliable PCB socketing system, and I don't have extender cards. I have a barely working Sony DSE 2000 on the workshop shelf too, and it is military in it's construction compared to the English and American units of the same vintage. There is also a Lexicon Prime Time on the dead reverb shelf, suffering from the dreaded "black chip leg" syndrome so it is quite a little collection of reverb history looking down on me each day from the dusty shelf near the ceiling. The AMS is the only one that it is probably worth putting any effort into.
 

Steve Jones

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Thanks Jakob for the hints, I will try them tomorrow. As I said, I have service manuals, but they are like a phone book.... Yikes.
 

Michael Tibes

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Hi Steve,

It's been along time since I had to fix those devices and I don't know if what I remember is from the AMS-Reverb or the delay unit. Anyway, I think the basic 'building style' is the same and so might be the problems:
- Obviously a careful cleaning helps, especially on the gold contacts of the inserted pcbs.
- The backup battery circuit is missdesigned and overcharges the NiCd. Assume this to be broken.
- All the modules are connected with flatwires, these tend to rub at the pcbs, causing shortcuts in the long run. Examine them all very carefully and fix the insulation.
- Changing the power supply fan's blowing direction from blowing out of the device to into the unit and adding a dust filter in front of it keeps the thing happy for a longer time without frequent cleaning.
- Some programs were delivered separately - printed on paper as barcodes! Haven't seen such a reader for ages... I don't know which programs were permanent and which were optiional...

Hope this helps a bit.
Good luck, it's worth the effort! :grin:

Michael
 

SSLtech

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The barcode reader required the remote unit, which also required a specific software revision. Also, early remotes also required updating... (ours wouldn't work with the barcode)

Resetting the unit (powering on while holding down the number [1]...) loses any barcode settings in memories 10, 11 and 12.

Keith
 

ladewd

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The biggest problem with these is the Ni-Cad battery leaks and destroys the traces on the CPU board.  Some chemicals and 30 gauge wire are required to fix it.  Lots of fun, but worth it as units are selling for a good amount these days.

CA
 

MagnetoSound

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ladewd said:
The biggest problem with these is the Ni-Cad battery leaks and destroys the traces on the CPU board.  Some chemicals and 30 gauge wire are required to fix it.

Reading this, I am reminded that this is one of the things I dread happening to my beloved rmx.

Thinking now that I will just pull it out of the rack and change the battery BEFORE it needs doing ...

So, is it OK to just swap the battery out with the unit powered down? Will it lose any stored data when I do this?

I can live with writing down any saved patches beforehand, but it won't do anything else, right?

 

Michael Tibes

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If I remember right (I haven't been close to an AMS rev for many years) there used to be additional programs available, printed barcodes that were read with a barcode reader. :eek: I believe those would be lost as well - and certainly hard to restore without a working reader.

Michael
 

skal1

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hey lads

i have one of these  baby's to but the output  is  crackling when you run the audio through it , were is the best place to look for this fault ,which card is the output card.


skal1



 

MagnetoSound

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Michael Tibes said:
If I remember right (I haven't been close to an AMS rev for many years) there used to be additional programs available, printed barcodes that were read with a barcode reader. :eek: I believe those would be lost as well - and certainly hard to restore without a working reader.

Michael

Of course! Thanks, Michael.

I don't think I have any of the additional programs in there, but I will check before I go ahead.

 

ladewd

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The DAC is the 4th card from the left.  It faces a different direction than the digital cards.  Crackling could be that, or one of the RAM cards.  I have also seen the sampler card (2 from left) cause crackling.  After the DAC, the audio goes through some analog IC's on the Exponent control board which is to the right of the DAC.  Hope this helps.

To answer another question, yes you will lose your presets when you change the battery.  The barcode program sheets are tough to come by but the RMX is capable of holding 12 algorithms, even though they only shipped with 9.

CA

 

MagnetoSound

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ladewd said:
The barcode program sheets are tough to come by but the RMX is capable of holding 12 algorithms, even though they only shipped with 9.


Found some of the barcode sheets here. Got no way to read them, though.  ;D

 

skal1

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ladewd said:
The DAC is the 4th card from the left.  It faces a different direction than the digital cards.  Crackling could be that, or one of the RAM cards.  I have also seen the sampler card (2 from left) cause crackling.  After the DAC, the audio goes through some analog IC's on the Exponent control board which is to the right of the DAC.  Hope this helps.

To answer another question, yes you will lose your presets when you change the battery.  The barcode program sheets are tough to come by but the RMX is capable of holding 12 algorithms, even though they only shipped with 9.

CA

Hi ladewd


thanks for the pionter will have to take anoter look after xmas

skal1
 

ladewd

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I worked on a RMX the other night.  The order of the I/O boards (on the left hand side of the unit) is:
Analog Input, Sampler Board, ADC, Exponent Control board (With analog output), then a single multiplexed DAC.  I had it wrong on my other post. Sorry for any confusion.  Unlike the DMX delays, the slots are marked as to which board belongs where.  Some units used 2 memory cards and others used a single card with more memory.

Believe it or not, the RMX used a modified supermarket barcode reader as a remote and to load the extra algorithms.  Like everything AMS, I have not seen two remotes built alike.  The RMX's were pretty much built the same though.  Later models used a switching 5V regulator while early models used a linear supply with a huge MOSFET mounted on the rear panel.  They can be a bitch to fix, but I've fixed well over 100 DMX and RMX's in the last few years and I don't consider myself especially gifted.

CA
 
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