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2602 USA 2500 Verona 2320

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Verona

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Sultan

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2320 Sultan 3D

  

 

Go to the 2602 model page

 

Go To 2500 USA chassis used to power up a 2602 USA chassis.

 

 

BLAUPUNKT Sultan

This six tube restoration comes from a Ham Fest.  On inspection before dim bulb testing the chassis shows  repair attempts.  There are a few capacitors that have been replaced.  The Diode bridge had been replaced with four silicon diodes in a plastic pill box.  This will be replaced with a terminal board and dropping resistor or something more substantial.  There is heavy corrosion of the fuse and just about all electrical contacts.  The power switch shoes high resistance when closed and may need replaced if cleaning does not help.  The power cord has been kindly cut off.

I clipped a cheater cord onto the transformer primary, plugged the cheater into a 100 watt dim bulb tester and applied power.  The lamp stayed dim and the radio began to crackle to life.  Once on direct line power the radio picked up stations on the AM broadcast and FM bands.  Rather distorted but this is a great sign.  No worries about IF transformers and the tubes are functional.  The selector switch is in need of a complete cleaning as indicated by extreme crackling when the slightest tough or vibration occurs.   There was no evidence of sound coming from the left or right tweeters. The EM80 tuning eye indicator is dark. 

There looks to be a missing choke on the under side of the switch assembly.  This will have to be investigated and replaced.  The whole chassis need be compared to a chassis for any other modifications.   It turns out these are two long wave band alignment capacitors.  The fine wire coiled around the thick enameled copper stub needs to be wound or unwound to adjust the capacitance.

Further inspection shows many capacitors are original.  There is a burnt original resistor in the audio section.  Perhaps an output tube shorted or is shorted. This will be thoroughly investigated during restoration. Also an extended burn in period is to be run to shake out any bad parts (i.e., the corroded and rusted power transformer.

 

Restoration Photos

Electrostatic tweeter is dead. Corroded contact.
Deteriorated foam dose not press the conductive film against the contact. Donor foam rubber. Make holes with a hot instrument. Hot wire slice in two. The wire has been recovered from a cement high watt resistor. Hotwire in series with a 100 watt bulb and variac. Rust.  Sanded and sprayed lightly with clear lacquer for insulation.
All apart. Underside restored. This needs patched.  Most of the veneer was saved and glued back on. Most of the veneer was separating from the base.
This gasket turns into powered when touched.      

 

IMG_0945.JPG (875627 bytes)The bezel receive the standard Clorox Clean up and Magnolia's Glayzit.  IMG_0946.JPG (683729 bytes)  The tweeter speaker grills were subjected to the same cleaning.  IMG_0947.JPG (681780 bytes) IMG_0948.JPG (694765 bytes) IMG_0944.JPG (1136452 bytes) IMG_0943.JPG (1101243 bytes)
  IMG_0949.JPG (436635 bytes) IMG_0950.JPG (633045 bytes) Good Night.  

 

Silver Mica capacitor Disease  The crashing thunderous roar in the AM band.

 

After hours of burn-in this radio developed static.  It started as an occasional pop.  Like the sound you get when some one turns an appliance on or off.  It just progressively worsened.  And the eye tube seemed to be fluctuating with the AM modulation.  So I embarked on the delicate task of disassembling the IF cans, removing the internal mica wafers and adding external silver mica 600 volt caps.  Join me below.

 

IMG_0888.JPG (674635 bytes) Take a photo of the wiring to the IF cans. IMG_0889.JPG (821203 bytes) Get different angles. IMG_0890.JPG (744055 bytes) IMG_0891.JPG (744091 bytes) IMG_0892.JPG (845646 bytes) After carefully marking what coil connected to which lug I unsoldered the fine wires.
IMG_0893.JPG (636612 bytes) IMG_0894.JPG (660761 bytes) The base contains the wafer caps. IMG_0895.JPG (926947 bytes) If the values are not marked on the schematic measure and mark the value on the base. IMG_0896.JPG (874444 bytes) Yes with the low voltage of the meter it will read the mica wafer's capacitance rather accurately IMG_0897.JPG (635271 bytes)Remove the rivit.
IMG_0898.JPG (856094 bytes) Wimpy wimpy IMG_0899.JPG (762965 bytes) Grunt Arg (Tim Alen). IMG_0900.JPG (561606 bytes) Now that rivet is gone. IMG_0904.JPG (685313 bytes) pry it apart. IMG_0905.JPG (606035 bytes) See the caps.
IMG_0906.JPG (608040 bytes) The blackened area is the trouble spot. IMG_0909.JPG (508462 bytes) IMG_0910.JPG (591209 bytes) IMG_0911.JPG (759755 bytes) Snip off the contacts but leave a bit so the lugs do not fall out of the base.  IMG_0912.JPG (629898 bytes) Hot melt it back together. 
IMG_0913.JPG (752057 bytes) IMG_0914.JPG (521939 bytes) Mount your new caps.  1) 250pf and 1) 150 pf.  IMG_0931.JPG (716385 bytes) Installed.    

 

Now for a quicker way to remove the mica wafers.

IMG_0916.JPG (697214 bytes) Take a wiring picture.  Saves schematic tracing.  IMG_0917.JPG (669877 bytes) Move the lower slug out of the way.  You will have to aligne the IF after all this work for accuracy.  IMG_0918.JPG (394482 bytes) See the caps? IMG_0919.JPG (551794 bytes) Snip the long contacts leaving a bit so the lug stays in the base.  Yes, the coil wires are still attached.  IMG_0921.JPG (524623 bytes) See how short. 
IMG_0922.JPG (566385 bytes) IMG_0923.JPG (512164 bytes) Uncut side.  And Mark the cap values on both sides.  You can not use a cap meter with both coil wires attached.   IMG_0924.JPG (546363 bytes) The schematic has the cap values marked. IMG_0925.JPG (611374 bytes) Replace the cover IMG_0926.JPG (642085 bytes) I use a clam since the hot melt gun is industrial grade heat!  
IMG_0927.JPG (521135 bytes) Shoot some glue in the holes. IMG_0928.JPG (615940 bytes) Move the slug back to where you think it came from.  Not critical since you will be though and do a complete alignment.  IMG_0930.JPG (757029 bytes) Reinstalled.     

The sensitivity all bands increased dramatically.  I picked up several beacons on the long wave band below 350khz.  The eye tube stopped bouncing to the music.  FM was unaffected.  There are not caps in the FM IFs.

It helps to use an earth ground with the LW reception. There are no RF bypass caps in this chassis. Besides to bypass (ground) LW may permit too much AC line current leakage.  

 

 

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