Well now, That's an interesting find. REVOX B790

[blhagstrom]

Unbelievable ! I need to search through more junk piles

Was that Denon 301/304 on it ?!

No label showing.
Probably on the top where it can’t be seen.
Hate that.

 

[fishondwan]

Yep they are labeled on top, it should be one of the two though.

Nice cart and nice table, you did good !

 

[the_nines]

Beauty!

 

[blhagstrom]

Has anyone worked on one of these and knows the cuing?

This one doesn't drop without a push.
I am too swamped with other work to investigate just now.

If it's some trick electronic control that's goofy, it would take time to sort out.
If it's some sticky mech, I would take a shot at looking into it.

Maybe they open up easy to look but I havent even had that much time.

One problem with being handy, there are so many things that need to be fixed, a guy never catches up.

Another problem is a handy person has too much old stuff that is way past its expected lifetime and a lot can go wrong in a lot of stuff all the time.

Although, I can fix the old stuff, the new crap is crap.
Just threw away a $150 Keureg coffee machine after 4 years.
POS.

 

[BilboBaggins]

I see this all the time at the thrifts. The crap is what you will see the most of on the shelves. Like Keurigs. Also, for anyone using coffee machines, filtered water is a good way to extend their operating life. You would be amazed at how many machines are toast only because the water killed the machine! I used to repair espresso machines. Over the years, I've settled on only one type because the rest just aren't worth the effort unless it is a simple fix. Unfortunately, most of the issues are the vibe pump. $60 part and about 3 or 4 hours effort. And how much will you get for it once it's working? Not more than $150 no matter what brand of consumer model until you get into high end machines that aren't mostly plastic.

 

[blhagstrom]

I see this all the time at the thrifts. The crap is what you will see the most of on the shelves. Like Keurigs. Also, for anyone using coffee machines, filtered water is a good way to extend their operating life. You would be amazed at how many machines are toast only because the water killed the machine! I used to repair espresso machines. Over the years, I've settled on only one type because the rest just aren't worth the effort unless it is a simple fix. Unfortunately, most of the issues are the vibe pump. $60 part and about 3 or 4 hours effort. And how much will you get for it once it's working? Not more than $150 no matter what brand of consumer model until you get into high end machines that aren't mostly plastic.

I have an attitude abut the whole coffee BS thing.
Starbucks, Keurig, etc....
Proof that people are idiots and crap sells.

When I finally decided coffee was of some use, around 1990, and I was about 30.
Paul Harvey was still on the radio and Bunn was a sponsor.
Back when they cared what products were sponsors.

That Bunn is still in use.
Everyday.
I had to attend to the little rubber seal on the top of the tank once.

I have collected those machines from yard sales.
I should have a lifetime supply if one ever fails.

The wife, likes the Keurig.
Lucky thing I scored a new POS at Walmart on sale for 1/2 price.

I dug into the old one.
Our water is damn near pure out of the tap.
Our community has its own water treatment plant.
We drink our lake.
Our lake is one of the cleanest known in WA.
You could drink the raw lake except for the biologicals.

I doubt the Keurig problem is mechanical.
Fairly sure some POS IC has gone wonkers or some other dumb electronics BS has gone mad.
How much BS tech do you need to make water hot and soak coffee grounds to get a drink around here?

Rubbish!

 

[MRL_Audio]

^^^ appreciate that comment(s)!

 

[BilboBaggins]

I know this is slightly off topic again, but I still have a stovetop espresso pot, and a stovetop steamer for travel, camping, and emergency use. Once I get used to it, I get very good results. They have gone from the east coast to the west coast with me.

Ok, carry on!

 

[jim249]

Has anyone worked on one of these and knows the cuing?

This one doesn't drop without a push.
I am too swamped with other work to investigate just now.

If it's some trick electronic control that's goofy, it would take time to sort out.
If it's some sticky mech, I would take a shot at looking into it.

Maybe they open up easy to look but I havent even had that much time.

One problem with being handy, there are so many things that need to be fixed, a guy never catches up.

Another problem is a handy person has too much old stuff that is way past its expected lifetime and a lot can go wrong in a lot of stuff all the time.

Although, I can fix the old stuff, the new crap is crap.
Just threw away a $150 Keureg coffee machine after 4 years.
POS.

Mine was acting up like that. In the second picture of your first post is a silver looking can with a connector to the arm assembly. That is a damper mechanism and most likely needs to be cleaned. No lubricants should be used. There is a small hole in the bottom which is partially cover by the frame. You may need to rotate the can a bit to help with the dropping of the tonearm. That hole sets the arm rate drop speed.

 

[blhagstrom]

Mine was acting up like that. In the second picture of your first post is a silver looking can with a connector to the arm assembly. That is a damper mechanism and most likely needs to be cleaned. No lubricants should be used. There is a small hole in the bottom which is partially cover by the frame. You may need to rotate the can a bit to help with the dropping of the tonearm. That hole sets the arm rate drop speed.

Excellent, I’ll see if I can take a look into that.

 

[steerpike2]

Does the arm lowering solenoid pull in when you push the up/down button?
If yes, then the sticky lowering is a mechanical problem - needs cleaning of the dashpot, etc.

But if the solenoid does not pull in and hold, it is because the solenoid to lower the arm is operated from a voltage doubler circuit, so it gets a pulse of about 50V to engage it, and then is held in by about half that voltage. It uses a big electrolytic capacitor to hold the 50V, and as with ALL Revox B-series units, the electrolytic capacitors age badly. If that cap is leaky, it will not have enough of a pulse to pull in the solenoid, but it will hold if helped.

You MUST replace the Frako capacitors throughout, they WILL go short circuit soon. And also the Rifa suppressor across the AC input.

These were sold with AKG or Ortofon cartridges, very occasionally Elac. If it has a Denon in it, that is not original.

 

[blhagstrom]

Does the arm lowering solenoid pull in when you push the up/down button?
If yes, then the sticky lowering is a mechanical problem - needs cleaning of the dashpot, etc.

But if the solenoid does not pull in and hold, it is because the solenoid to lower the arm is operated from a voltage doubler circuit, so it gets a pulse of about 50V to engage it, and then is held in by about half that voltage. It uses a big electrolytic capacitor to hold the 50V, and as with ALL Revox B-series units, the electrolytic capacitors age badly. If that cap is leaky, it will not have enough of a pulse to pull in the solenoid, but it will hold if helped.

You MUST replace the Frako capacitors throughout, they WILL go short circuit soon. And also the Rifa suppressor across the AC input.

These were sold with AKG or Ortofon cartridges, very occasionally Elac. If it has a Denon in it, that is not original.

This is what makes AK great.
The info of use plus more.
It seems I have another repair job on my list.

Thank you.