Philips EL3541/15B

[Davidcraig]

I am trying to restore my Philips EL3541/15B - a Christmas present from parents back in 1961 - but I need some expert advice!

The motor and all mechanics function correctly, new belts and reel 'nubs' fitted. Lubrication as per Service Information. All switches and pots cleaned, all valves replaced. C11 (50uF), C21 (32uF) and C22 (32uF) replaced.

'PA' mode (mic and line inputs) works fine.

'Record' mode (input from sig gen) - no movement of 'Magic Eye' (EM84) and very low record level. Same with both mic and line inputs.

'Playback' mode - very low output from known good pre-recorded tape.

'Record' and 'Playback' problems are not affected by the position of the 'Track' selector switch.

I have the cct diagram but very limited test equipment (Fluke multimeter and AF sig gen).

I'd be most grateful for some help!

David

[Davidcraig]

Poking about with my multimeter has revealed an open-circuit anode load resistor on V3 (ECL82j. Not in stock so having to order.

What other caps and resistors in this recorder are known trouble-makers?

Thanks

[Michael Maurice]

i would check/replace R3, R7, R9, R10, R19, R26 R34 & R35. R26 is the resistor you've found to have gone high.

I dont know what capacitors are used in these machines, but check/replace C6, C7, C12, C13, C19 and C24.

[Richardgr]

A lot depends on the quality of the components you have. Are you able to share some pictures here?

I have 'revitalised' a couple of 60's tape recorders, and both were transformed by a wholesale capacitor change. The non-electrolytics were Rifa capacitors, and every single one had a crack in its body so had been able to absorb moisture.

[Studio263]

I think these use the familiar Philips 'mustard' type capacitors for the smaller values. They are better than the new ones, leave them alone!

[DMcMahon]

Looking at the parts listing virtually all of the non electrolytoic capacitors are listed as Ceramic or Polyester. These type of capacitors generally give few problems.

Looking at one of my EL3541 machines virtually all of the non electrolytic capacitors are the yellow mustard type, these were a Polyester film capacitor and as Studio263 says they are a known good type with rare failures.

I would additionally recommend checking electrolytic capacitors C1, C3 and C20, these are cathode bypass capacitors for V1, V2 and V3 respectively. Potentially electrolytics of this age could be electrically leaky.

If you are competant and can do it safely, you could just measure the DC voltage values at the cathodes to ensure they are close to the values shown on the schematic, these are only low voltages, but of course there will be higher voltages present on some of the other close by pins of the valves, so be careful.

David

[Chris55000]

. . .Beware of the tertiary feedback winding on the output transformers of both this model and the three speed EL3542 – it does go o/c which results in distorted reproduction amd a generally higher hum and noise level – check the windings against the pin drawing sketch on the circuit diagram with a multimeter! I've got a '3542 needing an output transformer to rectify this fault, and there's none for sale at the moment!

Chris Williams

[vidjoman]

Looking at your original post - if the PA mode works fine then it possibly points to the PA mode switch that is loosing the signal for record/playback. I assume that the heads are very clean and the pressure pad is in the correct place.

[DMcMahon]

That is a very good point, but it is difficult to understand how it worked OK in PA mode with an open circuit anode load resistor on V3 ?

David