[HPower]

Sorry

Yes, I did try it with the new tube and the cover off and it blew the fuse just like before.

[SCompRacer]

HP, sorry to hear your not up and running.  You probably are, but I have to ask, are you using slow blow fuses?

[cwt108]

You are definitely not the only one alone.

I purchased my unit (Modwright sony 9100ES signature with P.S. 9.0, SWL 9.0 SE with tube, and Ciaudio d200) around mid of February. The fuse for P.S. 9.0 (the power supply for sony 9100es) blew off. I quickly asked Dan about this issue and received tube replacement from Dan around one week. According to Dan, he believed that the tube probably went wrong. I replaced the tube and fuse last night. The unit is working again. I played it maybe 2~3 hours last night and everything was fine. I left it on for another 2~3 hours this morning and then the fuse blew again. I replaced my last fuse from Dan and it went off again. I am not sure what is the problem. If the tube is the issue, then my replacement tube only last 5~6 hours... that is outrageous to me. First, I am not a technical person. I expect that at this kind of price level (7k+), I should not worry about this kind of technical issue... either bad tube or something other things. I am still waiting for Dan's reply (since it is already weekend... probably would not hear back from him anytime soon).

I believe that Dan will resolve this issue eventually. It has been a great expereince to do busienss with him. However, if many of us have similar issues, maybe Dan should start to pay more attention to this issue and fix it proactively. It will be very frusturing if problem keeps coming out, but there is not obvious solution.

Maybe this kind of issues happen often to experienced users. However, for a novice like me, it is really not a good and very expensive experience.

[HPower]

Hey SCompRacer,

Yep, I have been replacing with the 2A slow-blow fuses as Dan had specified.

cwt108, I am also very confident that Dan will get to the bottom of the problem, 
but as I mentioned, my biggest concern is the down time.

[cwt108]

HPower,

I have my electrician friend (30+ years experience) checked out my PS. 9.0. He could not find anything wrong with the power supply unit and believed that Dan was probably right about those tubes. Some of them have issues. I was just surprised that even the replacement still had the same problem.

I am still waiting for Dan's reply. At the mean time, I plan to purchase the tube (probably higher quality ones) on my own for backup. Ironically, I currently could not locate the fuse type that Dan wants. I purchased some 2A Slo-Blo fuse from the local Radio Shack. Dan told me that I need to get another type of fuse with thick wires. I could not find it anywhere. Do you know where I could find this kind of fuse???

Dan is used to reply back to me quickly,too. I guess that he is very busy about his new products. Hopefully, I could get a hold with him soon.

[SCompRacer]

After I replaced the bad tube in my 9100ES PS with a Mullard I had, I was able to use the 2A Radio Shack Slow Blow fuses.  Part # 270-1064.  The fuse wire danced around a bit when it started up but it didn't blow.  Dan had sent me the beefier slow blow fuses so I keep the Rat Shack fuses as spares.

[HPower]

I also got the fuses at "The Source" (formerly Radio Rack here in Canada).

I just double checked and they are 2.0A, 250VCA, 5 by 20mm.
The part number on my package is 2701172 and they are made by Nexxtech
and distributed by Orbyx, and manufactured in China.

I have been tempted to try a 2.5A or 3.0A but am afraid to cause any serious
damage if it is not the fuse that is the problem.

[modwright]

Hi guys, I am well aware of the problems that a few of you have had with the tube-rectified supplies.  I do believe the problem is related to rectifier tube failure and at least some of this is due to a small percentage of the 5AR4's that we stock being defective.  I have already first of all implemented a lengthier burn-in and Q/C process, involving multiple startups and shut downs, to locate defective tubes before they leave here.

I have researched the design limits of the tube again to be doubly sure that we weren't asking it to do anything it isn't rated for, but we are definitely not.  I believe the problem has to do with inrush current at startup.  We use slo-blo fuses as there is an instantaneous current spike at turn on.  It is possible that the defective tubes are not reacting well to this.

I sincerely apologize to those few who are having difficulties here and you know that we will do whatever is necessary to resolve the issue.  As I said, we are also taking preventive steps going forward to isolate these issues as part of lengthier Q/C and burn-in periods.  The problem does seem to appear either right away or not at all.

Thank you,

Dan W.

[HPower]

Hey Dan,

Would you say it would be a    to use a 2.5A or 3.0A slo-blo fuse?

It sounds like it might be a catch 22 with the higher amperage fuse, a 3A fuse might
survive the start up better but then might not offer enough protection after the start up?

[HPower]

Well, I am happy to report that I finally got my replacement tube and a fuses in the mail from Dan and everything
is back up and working fine.
It seems that the Radio Shack 2A slo-blow can not take the inrush current at start-up but the 2A fuse that Dan
supplied me does the trick.

[modwright]

I would recommend only using 2A slo-blo fuses.  It is increasing risk of product damage to use higher-rated fuses.  In the case of the 'audio' fuses, I have found that it is necessary to go up to the next size in order to prevent turn-on failure (of fuse) because they are not the right type of slo-blo fuse.  I would just recommend caution when going up in fuse size.

Dan

[HPower]

Hey Dan,

Other than buging you, what brand and where can we source the correct 2A slo-blo fuses?
I know the 2A slo-blo ones that I got at The Rat Shack did not work like your fuses.

[modwright]

W buy them from Buss fuses, part #: BK/GMD-2A.

Thanks,

Dan