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Jolida 801 V4 & V5 Tubes not powering on

Tuned

Tuned

New Member
I'm new to the forum and looking for some tips to help troubleshooting.

I've had my Jolida 801 for about four years. It's worked great but today two of the tubes are not powering up. Ports V4 and V5.

I put a basic multimeter on to check each tube ,as per the manual bias guide, and no voltage shows up for the two of them.

First thought I had was are there fuses that sit behind these maybe? I haven't opened the unit up as yet.

Any troubleshooting tips would be really gratefully received.
 
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Did it just quit working or do you just not see the tubes lighting up?

Without pics, I am just guessing that these are preamp tubes?
 
Pretty unusual that they both go out at the same time. Probably something else wrong underneath. Can you open it up underneath and have a look?

Are V4 & V5 two of the 6550/EL34 power tubes or the 6SN7 preamp tubes?
 
cademan said:
Did it just quit working or do you just not see the tubes lighting up?

Without pics, I am just guessing that these are preamp tubes?
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These two tube ports seemed to just stopped working, the other tubes work.
 

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cademan said:
Pretty unusual that they both go out at the same time. Probably something else wrong underneath. Can you open it up underneath and have a look?

Are V4 & V5 two of the 6550/EL34 power tubes or the 6SN7 preamp tubes?
Click to expand...

It is odd that only two have stopped working. As part of trying to see what might be wrong I replaced the four 6550 tubes we new ones (I had four unused tubes). So it does seem like something more with the unit underneath and I can't seem to find a diagram of how this is wired. Seems like I'm going to have to try and figure out how to get inside the unit.
 
vinylkid58 said:
Was the amp new when you bought it?



That pretty much confirms that the tubes are dead. Time for a new quad. What's in the amp now?

jeff
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Brand new purchase. First real issue I've had with this unit, it's been working just great up until this.
 
If you are so inclined, check out the heater pins 2 & 7. Could be something simple as a loose or unsoldered wire or something more sinister as a burnt wire.
 
Careful there! Lethal voltages inside a tube amp and the capacitors can hold a charge for quite a while. Unless you know what you are doing do not poke around the insides. You can look and see if anything looks burnt or loose but do not touch.
 
Tuned said:
Brand new purchase. First real issue I've had with this unit, it's been working just great up until this.
Click to expand...

Call or write to Jolida ( https://www.jolida.com/contactus ). If replacing tubes with known good ones does not help, you need a professional repair. If you do not have skills at least at electronics technician level - you better leave it to a professional. It is likely time to send amplifier for repair.

I looked at available schematics of various Jolida amps, and it looks they like to have separate heater windings in power transformer for each pair of output tubes. That can explain only two tubes loosing heating power.
 
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ejman said:
Careful there! Lethal voltages inside a tube amp and the capacitors can hold a charge for quite a while. Unless you know what you are doing do not poke around the insides. You can look and see if anything looks burnt or loose but do not touch.
Click to expand...

You are right. I'll look to see about a professional repair.
 
for_p1 said:
Call or write to Jolida ( https://www.jolida.com/contactus ). If replacing tubes with known good ones does not help, you need a professional repair. If you do not have skills at least at electronics technician level - you better leave it to a professional. It is likely time to send amplifier for repair.

I looked at available schematics of various Jolida amps, and it looks they like to have separate heater windings in power transformer for each pair of output tubes. That can explain only two tubes loosing heating power.
Click to expand...

Thanks for the advice.

I'll email them to see how I go about having the unit looked at. No idea what the cost will be but I really want this unit back up and running.

I really do appreciate all the advice, I've learned a lot since starting this thread.
 
Try and find a local tech. Jolida may be able to recommend someone closer to you. That way you won't have to box up the amp and ship it.

jeff
 
vinylkid58 said:
Try and find a local tech. Jolida may be able to recommend someone closer to you. That way you won't have to box up the amp and ship it.

jeff
Click to expand...

Will do, that's good advice.

I really don't want to ship it if possible in case it gets damaged. Plus the weight will no doubt sky rocket the price to ship it. Thanks.
 
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