Alesis HD24 repair/upgrade

[Tubetec]

So I found a HD24 going cheap ,
Guy offered to drop the thing to my place .
Anyway he arrives , we plug in the HD24 .......... nothing ,no spark or flash or bang , dead ,but he insisted it had been working .

Anyway I struck a deal on the unit at an even more reduced price ,
Turns out theres an issue that arises in the Smpsu , theres an AC to DC convertor right around the input ,
takes in mains power ,puts out 5.7vdc .
This component has a habbit of blowing up , TOP227YN is the modern equivalent
Looks like its an easy job to replace .

The unit contains the usual dual IDE caddy HD , only one drive was included ,
I'm interested if anyone has any of the Sata drive caddies for the HD24 left lying around ,
Seems like a few of our members here used these machines in the past , so just let me know if you happen to have any spares left over .

 

[Tubetec]

So I got to dig down into the main HD24 forum , theres some solid advice there ,
The hard drive caddies ,as there supplied dont mate well ,
There were quite a few issues reported from people who used the HD24 live and experienced problems with reliability because of vibrations ,
I took the advice from someone on the forum ,added a couple of 0.5mm thick washers between the header and the caddy ,now it mates up with much more satisfying engage and lock down of the carry handle, at best it was marginal before ,no wonder people had failures.

I got to check out the problematic psu a bit closer ,
good quality , all through hole ,high quality caps everywhere , plenty of space to cool and good screening between adjacent sections ,then old style linear regulators with fat bypass caps 2x 2200 per rail ,with a high current inductor forming a CLC at the ouput .
Alesis dont provide any service info on the psu , simply reccommend replacement from some supplier who no longer exists , so repair is the only option .

I found the the main AC/DC ic , TOP227 is still available , that needs replacement , it blew its top The opto isolator is also a readily available 6 pin DIL , I'm measuring and I dont see any sign of a diode on the in or out circuit , same ohms even when I reverse the +/- on the meter, Im going to assume its broken and replace it , theres a few other transitors nearby , they all measure good cold ,no sign of burned or scorched components anywhere .

I also found the transformer core in the Smps had broken loose from the bobbin, a few strategically placed globules of cyano gel locked it back down where it belongs ,

Ive had a check around on availabillity of the Alesis SATA caddys , pretty much extinct ,
I think for now I'll just make the best of the IDE ,
A later laptop style IDE drive should be able to do the job quieter and without needing the 12v rail so easing the load on the psu and reducing heat inside the case .

A closer inspection of the inside of HD24 reveals adapter cards at the back of the drive caddy enclosures , looks like it goes to 50 pin SCSI and back to the HD24 main board
So even if your using the correct Alesis SATA caddies , your going from an SATA drive to an SATA to IDE adapter ,then an IDE to SCSI adapter to the motherboard , its bound to become problematic .

 

[Whoops]

Still easy to find the Caddy online:

Alesis ADAT HD-24 Caddy

Removable hard drive media caddy for the ADAT HD24.

www.recordcase.de

Alesis HD24 Caddy +WD Caviar 250GB Hard Drive FREE USA Ship FREE 60-Day Returns! | eBay

HD24 Caddies! — HD24 compatible caddies arrive ready to plug and play. NOTE: I just got in a new batch of very clean Western Digital Caviar SE black drives, made in Thailand (see pic below)! — Seagate, WD, or Maxtor 7,200rpm IDE drives.

www.ebay.com

Alesis HD24 Caddy W/82G drive | Reverb

NOS drive that’s in a slightly used caddy, been stored in climate controlled studio

reverb.com

 

[Tubetec]

Thanks for that Whoops ,
All those caddies are IDE , I have two of them that came with the machine ,
Its really the SATA enclosures I want to try .

Did you have any experience using SATA drives with the HD24 in the time you used them ?