Lightning Damage to 9090DB

The fuses that are blown are the two clear 10A fuses on the left side of the fuse board (the front of the reciever is facing me).

I do not know if the ceramic 10A fuses are blown or not (located near the middle of the fuse board, oriented front to back of receiver). I suppose I could test those using my multimeter. What is the reason that ceramic fuses were used in place of the clear type? The rating is identical. Are there pros or cons to the ceramic type, or are they for a specific application?

I may try the test described above by removing the preamp board. Even though the description sounds easy, this is much more ambitious than any of my previous tampering with electronics. I would hate to mess this thing up. If I find out the output transistors are gone (which sounds like the better scenario of the two), is this a DIY type project?

Thanks again for all the help. This is a great site.
 
What is the reason that ceramic fuses were used in place of the clear type? The rating is identical. Are there pros or cons to the ceramic type, or are they for a specific application?.

Other than you can usually 'see' if the fuse is blown if it's glass, and with ceramic bodied fuses you can't - no.

Glass fuses are used for lower current situations - up to say 15A, because they are not so good at withstanding the forces & heat produced when the fuse ruptures. Ceramic fuses are much stronger and can be used for much higher currents with consequent increase in the forces and heat involved when they rupture. Ceramic fuses are very often filled with sand which absorbs much of the force and heating produced when the fuse ruptures.

I may try the test described above by removing the preamp board. Even though the description sounds easy, this is much more ambitious than any of my previous tampering with electronics. I would hate to mess this thing up. If I find out the output transistors are gone (which sounds like the better scenario of the two),....

For pre-amp board I think you should read 'Driver Board' :scratch2:

.....is this a DIY type project?.

.......Unfortunately, my expertise is severely limited on any type of electronic equipment.

Personally I think it's tech time for your 9090...
 
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I have been bracing myself for the realization of tech time.

It is hard for me to accept spending more money on this unit, as great as it is. I have only had it for a year, and I have more than $600 in it already. The repair cost is a huge unknown at this time, and I imagine anyone would charge $150 just to peek at it.

It makes me wonder if I should start watching ebay again.
 
And how much do you think a different one will run? Buying one ebay is a gamble. The different one may need some repair as well.
 
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the fuses that blew again may well have to be slow blow . do your old ones have a T marked on the end cap ?
 
In order for a 10A fast blow fuse to blow 'IMMEDIATELY', the current draw would have to be well over 2X the fuse rating. That isn't something changing to a slow-blow fuse is gonna cure.
 
Regarding the new fuses blowing, it was IMMEDIATE, just to clarify.

I sure appreciate everyone's comments on this - this discussion has been extremely helpful.

I know it would be a risk to buy a new unit that could need repairs - whether 9090 or something smaller. But I bought the 9090 mostly because I knew it was top dog and I would hate to go smaller now. I have to say my old 5050 sounds unbelievably good also. That thing is no slouch at all.
 
Have it fixed...Avionic is in Ft. Dodge, and I'm in KC. And the 9090db is worth the effort.

Comparing repair costs to the cost of buying another used one from eBay isn't a fair comparison. The possibility of the new unit having worse issues is pretty good (and it sounds more like yours simply has a blown power amp, which sounds bad but on a 9090db isn't really that huge of a deal) and you also have to worry about the cosmetics of the new one and whether or not it will be packed well enough to make the trip without getting destroyed (which will be a huge hassle with eBay and the shipping company that would make a $250 repair bill look positively benign by comparison).
 
Seriously, a viagra spammer on audiokarma?

Anyway, don't most transistors draw less as they warm up? Wouldn't the result be that replacing with slow-blows might be the correct fuses. Does anyone have the service manual? What does it call for? The OP said that the originals had thicker filaments than the replacements, which sounds like a slow-blow.
 
There are no slo-blo fuses in any 9090DB, unless someone put them there. You have much more going on than fuses my man. Back to post 28..
 
after reading through it sounds like after the power outage the company brought the line voltage back up in stages ..thus making the amp not work properly .then wrong fuses installed causing them to blow instantly ...slow blow or as my electrician calls them "motor rated "will take the inrush current much more than fast blow ..
just been beat to it go back to above post
was this not already fixed anyway ?
 
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I took the unit up to Avionic a few weeks ago.

I watched him work on it for a while listening to his great system.

I decided to have him do a full recap as long as he has it.

Can't wait to get it back.
 
I have a 5000X, recapping made a huge difference. I mean, it was more than just a recapping that I did, but recapping makes a big difference.
 
Seriously, a viagra spammer on audiokarma?

Anyway, don't most transistors draw less as they warm up? Wouldn't the result be that replacing with slow-blows might be the correct fuses. Does anyone have the service manual? What does it call for? The OP said that the originals had thicker filaments than the replacements, which sounds like a slow-blow.

The spammer is history.....:yes:
 
I just wanted to post a follow up on my lightning-damaged 9090DB.

I got it back from Avionic on Friday evening, and finally got it hooked back up today. He replaced a few transistors and fuses from the lightning issue.

I also had him recap the whole thing, including the Dolby board.

This baby sounds superb! :banana:

Thanks again Avionic!
 
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