ITT Schaub-Lorenz 5000 Stereo HiFi (1968)
Conservation status and error analysis
The device was used in German-speaking countries in the late 1960s. Due to its longevity the electronics works
the device is still almost flawless. It is noticeable that the repairs are similar to those of the Electown AR-3000E. - This kind of
Aging weaknesses typically appear after a few decades.
View of the radio frequency tuning indicators attached above. The VU meter for the
The frequency search has obviously got stuck here, too, because it did not move after it was first put into operation. - This
must therefore be included in the list as a repair. The stereo display does not light up in radio mode with a stereo signal.
There may be a problem in the stereo decoder or just the light bulb is defective.
The lighting of the frequency tuning display also has no function.
The patina-coated switches are clearly visible on the control panel on the front of the device
and potentiometers. The solid wood panels attached to the side will also be refreshed. The potentiometers and switches are those
Contacts are still in astonishingly good condition.
Repairs recording
- Loosen the stuck rotary cap for the medium and long waves
- Clean switch and potentiometer
- Replace damaged power cord and retrofit with protective earth
- Replace indicator lamps
- Check ESR of capacitors
- Repair/ replace VU meter (no function)
- Repair stereo decoder (possibly only replace lamp)
- Refresh solid wood panels
- Dust the inside of the housing
- Clean the outside of the housing
Troubleshooting and restoration
Condition inside before the restoration
Picture above left: The secondary connection terminal is not safe and in
the worst case it can short circuit or creeping currents can arise at higher humidity.
Picture above right: the wiring of the from today's perspective, the primary and secondary side is not
ideal and is therefore being revised. Bottom left picture: The sieve electrolytic capacitors
some of the DC voltages still have values from the old series of standards. So is the large
electrolytic capacitor according to the scheme a capacity with 5000 uF. - We actually measured this value.
However, there are 4700 uF on the capacitor. Bottom right picture: The
The stereo display bulb has actually blown and needs to be replaced.
Condition inside after the restoration
Top left picture: The wiring and components of the primary power supply have been made
mostly revised in the device. A line filter approved according to VDE was subsequently installed according to
today's standard and the protective earth retrofitted to the housing.
As you can see, this is attached to the side of the power cord. As a side effect, the wiring is now the same
of the power switch and does not have to be moved back and forth on the device wall. In this way became distortions
like noise
(including audible 50 Hz hum on the power amplifiers) reduced. Picture above right: The electrolytic capacitors on the
Power supply board and on the power amplifiers have been completely renewed. Bottom left picture: The old secondary
connection terminal was replaced with a standardized power terminal. The obsolete
The interference/ noise suppression capacitor on the 30 V supply has been replaced.
Bottom right picture: The wiring of the lamps for
indicator lighting has been completely renewed and replaced by LED technology. The tuning capacitor
for the Long / medium and short waves could be loosen with the help of some contact spray and
now works perfectly
Renewal of the floor pan
What turned out to be another weak point in retrospect was the old floor pan of the device.
It was made of hardened cardboard. This is not only a fire hazard but the floor pan deformed especially at
the pressure points to which the feet were attached. That is why a new plastic floor pan was developed and manufactured.
Comparision before (left) and after (right)
Pictures above and below left: Before the repair.
Picture above and below right: After the repair. The renewed capacitors are clearly visible.
The retrofitted line filter, which is installed in the back left of the device.
The new wiring concept for the power supplies and lighting.
The lighting also works again after wiring and upgrading to compatible LED technology.
View after completion of the revision
Below you can also see the completely newly developed floor pan,
which not only looks unobtrusive like the old floor pan but also ensures better convection
(passive ventilation) in the device due to the ventilation openings on the side and front.
After carefully cleaning the housing parts, the buttons and switches
also shine with a slight patina that has well-earned over the years. The side-mounted wooden panels
made of solid walnut were completely treated with a new protective glaze, which is now colorless,
after the old brown glaze was removed.