Francophones

I'm not a particularly fluent French speaker, but I could probably sort out some technical instructions in French If you want to send them to me, I'll have a go (you should be able to work out my e-mail address).

Many thanks indeed for your kind offer. I suspect it will probably require a native French speaker to decypher, but who knows? :-)

The French tend to prioritise flowery language over clarity.

I'm not a native French speaker, but I may be able to help anyway. Fire away.

Well that's interesing as I had did think you might respond given some of the background you've revealed here in the past. I don't have the relevant page here right now, but will make it available tomorrow. It is only the one page and only one column of that, so nothing too onerous. I did show it to a genuine French chum of mine a few weeks ago, but he was stumped by the technical side of it and couldn't assist much, unfortunately. So it appears it needs someone who can speak French fluently *and* understands the process of radio alignment. I kind of guessed that might be you....

Many years ago Practical Wireless published an article about the French

If you post your text here, we can all have a go at it.

Sorry for the delay; took a bit of tracking down but I have it now:

Here's my version. I couldn't display the tables as tables, so I have repeated the headers as individual paragraphs. One or two bits didn't make sense, so I have indicated them with question marks. See the originalpublication for the diode probe circuit.

Beware, the text is scattered with roman numerals.

INSTRUCTIONS FOR ADJUSTMENT

Agjustment on 9v D.C.,

Adjustment of the final audio Push-Pull stage.

Insert a milliameter in place of the link at the Collector of AC 188 K (use point -x-). Adjust the quiescent current to 6.5mA by means of R410 (500 0hms). After adjusting the current, resolder the link.

Adjustment of the IF amplifier:

By means of R515, adjust the Collector current of T IV to obtain a voltage drop of 1.35V across the Emitter resistorR518

-----------------------------

Adjustments FM intermediate frequency 10.7 Mhz Switched to "FM".

Adjustment: F VII Couple wobbulator output to: MP5 Measuring equipment: Diode probe [as circuit] to F VII point 6 Adjust for: (a) Off tune. ( b) At maximum and symmetrical

Adjustment: F VI & F V Couple wobbulator output to: MP3 Measuring equipment: Diode probe [as circuit] to F VII point 6 Adjust for: (c) & (d) maximum and symmetrical

Adjustment: F IV & F III Couple wobbulator output to: MP2 Measuring equipment: Diode probe [as circuit] to F VII point 6 Adjust for: (e) & (f) maximum and symmetrical

Adjustment: FII & FI Couple wobbulator output to: ?close? to mixer Measuring equipment: Diode probe [as circuit] to F VII point 6 Adjust for: (g) & (h) maximum and symmetrical

Adjustment: Discriminator Couple wobbulator output to: MP5 Measuring equipment: Across 50 kilohm cable on MP11 (at audio input) Adjust for: symetricality. During this sdjustment the signal must be very weak so that FI doesn't limit.

-----------------------------

Adjustments AM intermediate frequency 460 Khz Switched to Medium Wave ["PO".]

Adjustment: F XIII & F XII Couple wobbulator output to: MP3 F III Measuring equipment: Test point ?? MP4 Adjust for: (I) & (II) maximum and symmetrical

Adjustment: FXI Couple wobbulator output to: MP8 Measuring equipment: Test point ?? MP4 Adjust for: (III) maximum and symmetrical

Adjustment: F X & F IX Couple wobbulator output to: CV AM, MP7 Measuring equipment: Test point ?? MP4 Adjust for: (IV) & (V) maximum and symmetrical

--------------------------

Adjustment of the AM oscillator and input stage.

When aligning Long Wave and Medium Wave, couple to the ferrite rod aeraial across the frame [????]. Short Wave alignmnet is done with the telescopic aerial unsoldered. The signal is injected by a 15pf capacitor into the telescopic aerial terminal.

Medium Wave Tuning dial set to 560 Khz Adjust oscillator for (1) maximum Adjust input circuit for (3) max Mixer sensitivity 13uV Oscillator output 60 - 90 mV

Medium Wave Tuning dial set to 1450 Khz Adjust oscillator for (2) maximum Adjust input circuit for (4) max Mixer sensitivity 14uV Oscillator output 60 - 90 mV

Long Wave Tuning dial set to 160 Khz Adjust oscillator for --- Adjust input circuit for (6) max Mixer sensitivity 13uV Oscillator output 65 - 95 mV

Long Wave Tuning dial set to 240 Khz Adjust oscillator for (5) maximum Adjust input circuit for (7) max Mixer sensitivity 10 uV Oscillator output 65 - 95 mV

Short Wave Tuning dial set to 6.6 Mhz Adjust oscillator for (8) maximum Adjust input circuit for (10) max Mixer sensitivity 5 uV Oscillator output 35 - 90 mV

Short Wave Tuning dial set to 15 Mhz Adjust oscillator for (9) maximum Adjust input circuit for (11) max Mixer sensitivity 4.5 uV Oscillator output 35 - 90 mV

---------------------

Oscillator and IF alignment

Tuning dial set to 88 Mhz Adjust oscillator for (A) maximum Adjust IF coil for (C) max Hiss level around 5 kT0 ... [No idea what that means] Oscillator voltage on Emitter of T II 75 - 85 mV

Tuning dial set to 106 Mhz Adjust oscillator for (B) maximum Adjust IF coil for (D) max Hiss level around 5 kT0 ... [No idea what that means] Oscillator voltage on Emitter of T II 75 - 85 mV

Notes: Inject the signal from an oscillator with an internal impedance of 60 ohms directly into the mixer. After alignment, coupled by 60 ohms, the fundamental of the oscillator into the input of the mixer must be less than 2 mV.

This was translated from German into French by someone who also did not know clearly what it all meant. Not everything makes perfect sense.

Also, while it doesn't say so, many of the adjustments interact, so you may have to go back and forth a few times. Anyway, here goes.

Jeroen Belleman

===============================================================

-- DC current adjustments (for 9V supply) - Adjustment of the push-pull audio stage: Cut the solder bridge marked -x- in the collector trace of the AC188 T11 and insert a current meter. Adjust R410 for 6.5mA. Restore the bridge. - Adjustment of the IF amplifier: Set R515 to obtain 1.35V across T4's emitter resistor R518.

-- Adjustment of the FM-IF stages. The radio should be set to "FM". Connect a wobbulator centered on 10.7MHz at MP5 and the diode detector shown at ZF VII (I think...) MP6. Detune ZF VIII (a). Then tune ZFVII (b) for a symmetrical maximum response. - Inject signal at MP3 and tune ZF VI (c) and ZF V (d) for symmetrical maximum response. - Inject signal on MP2 and adjust ZF IV (e) and ZF III (f) for symmetrical maximum response. - Inject a weakly coupled signal at the mixer (MP1?) and adjust ZF II (g) and ZF I (h) for symmetrical maximum response. - Discriminator: Inject signal at MP5, with a level low enough that no limiting occurs in the IF strip. Observe the signal at MP11 (audio amplifier input) with load impedance 50k. Adjust ZF VIII (a) for symmetrical response.

-- Adjustment of the AM IF (460kHz) stages. The radio should be set to "PO" (AM, 560-1450kHz). Connect a measurement instrument at MP4 (Weakly coupled). - Inject a wobbulator signal at MP3 and adjust ZF XIII and ZF XII for symmetrical maximum response. - Inject signal at MP8 and adjust ZF XI for symmetrical maximum response. - Inject signal at MP7 and adjust ZF X and ZF IX for symmetrical maximum response.

-- Adjustment of local oscillator and AM input. For short and medium wave, couple signal into the ferrite rod antenna using the frame. For short wave, remove the rod antenna and couple signal at the antenna connection through 15pF. Tune to 560kHz and adjust (1) and (3) for maximum response. Mixer sensitivity 13uV and oscillator output 60-90mV. Tune to 1450 kHz and adjust (2) and (4) for maximum response. - Set the radio to GO (Long wave, 160-240kHz). Tune to 160kHz and adjust (5) and (6) for maximum response. Mixer sensitivity 13uV and oscillator output 65-95mV. - Set the radio to OC (Short wave, 6.5-15MHz) Tune to 6.5MHz and adjust (8) and (10) for maximum response. Tune to 15MHz and adjust (9) and (11) for maximum response. Mixer sensitivity 5uV and oscillator output 35-90mV.

-- Adjustment of the FM LO. Signal from an RF generator with 60 Ohm output impedance injected directly at the mixer (MP1?) with a loaded signal level <2mV. Set the radio to FM. - Tune to 88MHz and adjust (A) and (C) for maximum response. - Tune to 106MHz and adjust (B) and (D) for maximum response, Noise level is about 5 times kT0. Oscillator output voltage 75-85mV (at T2's emitter).

Thanks, Jeroen. Geez, you just can't win with these bastards. I've got a 50 ohm signal generator and a 70 ohm one - but that's not good enough for 'em. No, they want me to splash out on a 60 ohm one and where am I going to source one of those?? And it doesn't stop there! I thought all my vintage servicing voltage reading requirements would be met when I bought an old analogue Avo with 20kohms/volt. But now it seems I need to scratch around for a

I have to say, fair play to you for that effort! It may or may not be

I don't think that matters all that much, really. Your VNA will do fine as a signal source and a scope will do fine to measure resulting signals and voltages. If really necessary, put ten ohms in series with your 50 Ohm source.

Jeroen Belleman

Yes, but you know what a *bitch* it is to find a purely resistive 10 ohms....

Use the 50 ohm one and add a 10 ohm resistor.to the connection.

Parallel a resistor across a modern10 megohm electronic multimeter - or just shrug and say it won't make mucch difference.if the meter resistance is a bit higher.

I seem to remember Grundig made their own test equipment, so they probably just quoted the specification of whatever they were using on the production line at the time.

A factory I worked in used interference from the fluorescent tube above the workbench as the signal for the initial test of the audio stages. One hand on the lamp and one finger on a screwdriver blade touching the centre tag of the volume control - but I don't think they included that test in the repair manual.

Maybe just a length of nichrome wire?

Jonesy

:-) University professors everywhere.

Still got parasitics. Avoiding them is a craft in itself.

You and Jeroen have pretty much nailed it between you, I reckon. But just so as our sausage-eating fraternity here doesn't feel left out, I'm posting a German version I managed to find:

I wouldn't worry about the inductance of an ordianry 1/4 -Watt resistor at the frequencies involved. The only point where it might make any difference is the VHF input and oscillator tuning - and I can't think you need a great level of accuracy to align a domestic portable radio.

It is even possible that they specified a 60-ohm sig gen because they knew that most of the available ones would be near enough at either 50 or 75 0hms. Another possibility would be to try to make you think you had to return the radio to their specialised service department for repair. The avarage radio shop (if there are any left) simply wouldn't care and would use whatever they had on the shelf above the workbench.