Zerhacker/vibrator-repair

endeavour

 

Page initiated on 1 November 2024

Current status: 4 November 2024

 

Ambro currently being engaged in getting Marc's electronic substitute Zerhacker/vibrator operating in conjunction with

a power-supply of a Feldfunk b power unit.

We encountered unexpectedly difficulties which were not foreseen in Marc's substitute design.

 

Ambro is now engaged in getting matters right for further tests.

Fore it, Ambro has first to remove the high tension (ca 90 V .. 100 V) electrolytic capacitors, as these are not of the hermetically sealed-off types.

They should be consider as faulty in all cases!

https://www.cdvandt.org/exh-48-electronic-zerhacker-vibrator.htm

 

However, unexpectedly the question came up: why not trying to get some of the genuine Zerhacker/vibrators operating again?

In almost all cases, even when you hear the typical bussing noise, the contacts should be carefully cleaned from oxide.

 

Eric brought in his EW-b (Empfänger Wechselrichter type b).

 

The hermetically sealed-off electrolytic capacitors are quite well visible

In the early stage its current leakage was 45 mA which later reduced to 1.35 mA and even tending lower after a while. 

 

The current meter is indicating 4.24 mA current consumption

Please view carefully the glass seals which allow a hermetically sealing-off from environment.

 

(R2196 ↓↓↓   R2196return)     

The schematic of the Ew-b Zerhacker/vibrator controlled power supply to the Torn E-b receiver

 

Let us notice within the red ellipsoid the electrolytic capacitors C 13, C 18 and C 19

These three capacitors constitute the capacitive smoothing circuitry directly interconnected onto the HT output terminals - A and + A (= anode voltage)

The electrolytic capacitors (2 x 700µF) (= C7 & C8) being also of the hermitically sealed off type. 

These modules, of which according to data provided on the web, 64000 units had been supplied.

 

The first measurements had been accomplished is such a way - that we supplied, say, 100 V parallel onto the capacitors C 18 and C 19

 

Measuring the current consumption with the HT electrolytic capacitors C13, C18 and C19

Being 8.35 mA

That the meter scale is indicating a negative sign - 8,35 mA is only due to the way the two test cables being connected onto our FLUKE 25 meter; when we would have inter-changed the red and the grey test-cables we would see an inverse current flow thus providing + 8.35 mA.

 

What we are doing is all quite basic, but necessary as to get an impression what the current status of the actual resistance the electrolytic capacitors are.

 

All the time the leakage current is reducing due to the chemical process inside the electrolytic capacitors.

This current flow is causing an increasing building-up an oxide-layer at the Al surface inside these electrolytic capacitors. The longer we wait the heavier this layer will become and the leakage will degrease accordingly.

 

Here the leakage current has reduced to 4.9 mA

Please bear in mind: these electrolytic capacitors being at least 80 years old!

 

The a bit yellow like looking "Schaumgummi" is still flexible and did not become brittle

The German chemical industry "IG-Farben" was a world top " Industrial Konglomerat".

 

Removing with care the contact oxidation with '600' or '1000' sandpaper

 

The tiny material between the two upper contacts in front should be removed which can simply be accomplished by means of a thin paper-sheet or that like

The comment is relevant, but this Zerhacker/vibrator sample is not the one shown on our films of today; as we opened a range of Zerhacker/vibrators.

Someone contacted Eric and added:

another potential failure mode to look out for is the rivet with which the contact point is mounted on de vibrator arm. I recently had one where I kept having bad contact despite my cleaning efforts; during running I noticed that the contact point itself was moving slightly as the rivet had worked loose just a bit. To fix it I applied some contact laquer all around the base of the contact. This fixed the contact point in place and secured a good electrical contact to the vibrator arm.

 

 

Some of the Zerhacker/vibrators at hand

I suppose the open one at the centre is our sample under test.

 

Eric made some nice video-recordings of their mechanism.

You might notice some flickering in the background, which is, in my perception, being caused by the fluorescence illumination in our museum.

 

Finally my YouTube films being of a different category, but are providing also some aspects of what we were accomplishing on Friday 1st November 2024.

 

Film 000212:    Is showing how we started without the application of a genuine Zerhacker/vibrator. Instead we directly derived a HT voltage from the power-supply on the bench; and connected its output voltage onto the circuitry of the smoothing capacitors C 18 and C 19 and indirectly (see R2196   R2196return) and indirectly onto C13 as well.   Our Fluke 25 meter being operated in the current mode and is telling us that the current leakage due to imperfection of the electrolytic capacitors has been reduced to 1.36 mA.

 

Film 000211:    The set up is supplying ca. 2.28 ...2.4 V (power-supply on the right-hand side) onto Eric's vibrator pack EW-b and we have inserted our first cleaned Zerhacker/vibrator device in the according vibrator socket.    The according schematic of the EW-b vibrator pack is visible. The right-hand Fluke meter is telling us that currently we supply the EW-b pack with: 2.28 V and the left-hand side Fluke meter is telling us that the HT output is 90.1 V across a load of 22 k say roughly 4 mA. However increasing the battery supply up to 2.4 V the output voltage increases up to just over 100 V.  (actually we read off: at 2.44 V and loaded 108...) The true vibrator hum can he noticed at Eric's video recording:    https://www.cdvandt.org/mp4/Exh-49-Zerhacker-triller-humm.mp4

 

 

To be continued in due course

 

 

By Arthur O. Bauer

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