Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Dec Mon 11, 2017 10:29 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 9 posts ] 
Author Message
 Post subject: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Oct Mon 30, 2017 8:12 pm 
New Member

Joined: Feb Wed 10, 2016 9:23 pm
Posts: 8
Hi,
This Wollensak reel to reel came with some mechanical problem which fixed but now i have low audio
I dont have scheme, Can some one help,
Thanks,


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Mon 06, 2017 7:59 am 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 9402
Location: Powell River BC Canada
Is the overall sound quality good, just low speaker volume?
Is the sound quality good when connected to external amplifier ?

What is playing, a known to be good stereo tape ?

Is the head clean. and not worn ?

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Mon 06, 2017 8:11 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31350
Location: Maryland 20709, USA
The starting point for diagnosing any problem is always the power supplies.
Check the voltages and compare them with known correct values.

If you have no schematic or test data...
With the unit OFF, remove all tubes.
Power the unit up.
Measure the AC voltage from one rectifier plate to the center tap.

Power the unit down and install the tubes.
Power the unit up and measure the DC voltage at the second filter capacitor.
Also measure the AC voltage at that same point.

The loaded DC voltage should approximate the unloaded AC voltage.
There can be a significant difference, but not more than maybe 20% or 25%.

For example, 350 volts AC should give a DC voltage of 300 to 325 volts.

The AC voltage at the filter cap should be a few volts.

If the DC voltage is low and/or the AC voltage is high, most likely the filter caps are bad.
Generally those should be replaced without even testing, as they're almost certainly bad.

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Mon 06, 2017 12:31 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 20620
Location: Annapolis, MD
"Wollensak 1580 manual schematic" produces lots of hits on Google, including sites offering schematics and manuals.

Many people replace filter capacitors before applying power to any tube equipment.

Quote:
the starting point is always the power supplies
Absolutely!! When I first start up (anything electronic). I have a meter connected to the DC supply at a point that will show the "loaded" DC voltage. In tube equipment, this means that I connect after the first series R or L in the filtering. During turn-on, watch the unloaded value, falling as the tubes warm up and start conducting. If behavior is rational, next check the DC current by looking at the voltage drop across that series element.

_________________
-Mark http://pixellany.com

"It's always something". --Gilda Radner (1946 - 1989)


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Mon 06, 2017 8:33 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 9402
Location: Powell River BC Canada
The complete service manual, in in Sams TR7 , Dec 1963. ( I have it here)

The machine also is a PA amplifier. A test of the PA function would show if the
tape side, is the thing causing low the low level.

If you pull out all the tubes. The B+ across the filters will rise to maximum.

The manual is critical. There are 14 production changes, not on the schematic.

All sorts of tricks! 1 " plugs needed for low level input, but 1 1/4 " for high level !

It is a wonderful machine, but a witch to work on, diagnostically. And I have
worked on this model, when schools , etc, were still using it. Good times !
Lousy pay !

Attachment:
W T1580  try classified  someone may have  SAMS TR 7.jpg
W T1580 try classified someone may have SAMS TR 7.jpg [ 138.96 KiB | Viewed 348 times ]

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Mon 06, 2017 9:11 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31350
Location: Maryland 20709, USA
radiotechnician wrote:
If you pull out all the tubes. The B+ across the filters will rise to maximum.

That would be true if the load current was zero, which is seldom the case.

There are generally passive current paths in the system.
Not the least of these is leakage current through the filter caps .

- Leigh

_________________
73 de Leigh W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Fri 10, 2017 3:26 pm 
New Member

Joined: Feb Wed 10, 2016 9:23 pm
Posts: 8
Thanks Everyone who helped me,
Found 4 caps cathode to ground of 7591 Output C 4/ 100 u f@12 v odd size
i use 100/25 volts and Pre amp 6EU7 50 uf at 3 volts, Now clear audio no hum
Thanks,


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Fri 10, 2017 3:51 pm 
New Member

Joined: Feb Wed 10, 2016 9:23 pm
Posts: 8
My this repair detail is also picked up by "The Speaker" Newsletter by NESDA Ohio on there December 2017 Issue i will attached that copy later,
Thanks,


Top
 Profile  
 
 Post subject: Re: Wollensak 1580 Reel To Reel Low Audio on Both Channels
PostPosted: Nov Wed 15, 2017 2:00 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 17953
Location: Warner Robins, GA
The filter caps if not already replaced will also need to be replaced.

Also any capacitor that is not ceramic or mica or film needs to be replaced.

Check all resistors and replace all that are out of tolerance.


Top
 Profile  
 
Post New Topic Post Reply  [ 9 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 7 guests



Search for:
Jump to:  


















Privacy Policy :: Powered by phpBB