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Bi-Ampli BX998A

Bi-Ampli BX998A; Philips; Eindhoven (ID = 41781) Radio
Bi-Ampli BX998A; Philips; Eindhoven (ID = 41782) Radio
Bi-Ampli BX998A; Philips; Eindhoven (ID = 41783) Radio
Bi-Ampli BX998A; Philips; Eindhoven (ID = 41784) Radio
Bi-Ampli BX998A; Philips; Eindhoven (ID = 41785) Radio
Bi-Ampli BX998A; Philips; Eindhoven (ID = 41786) Radio
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Bi-Ampli BX998A; Philips; Eindhoven (ID = 1783688) Radio
Philips; Eindhoven: Bi-Ampli BX998A [Radio] ID = 1783688 933x620
Select picture or schematic to display from thumbnails on the right and click for download.
For model Bi-Ampli BX998A, Philips; Eindhoven (tubes international!); Miniwatt
Country:  Netherlands
Manufacturer / Brand:  Philips; Eindhoven (tubes international!); Miniwatt
Year: 1955–1957 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 16: EBF80 ECH81 EF80 EC92 EM34 EF89 EBF80 EF85 EAA91 ECC83 EBC41 PL81 PL81 EL84 EZ80 EZ80
Semiconductors (the count is only for transistors) OA50 OA72
Main principle Superhet with RF-stage; ZF/IF 452/10700 kHz; 3 AF stage(s)
Tuned circuits 9 AM circuit(s)     11 FM circuit(s)
Wave bands Broadcast, Long Wave, more than 2 x SW plus FM or UHF.
Power type and voltage Alternating Current supply (AC) / 90; 110; 125; 145; 180; 200; 220; 245; Volt
Loudspeaker 2 Loudspeakers
Power out
from Model: Bi-Ampli BX998A - Philips; Eindhoven tubes
Material Wooden case
Shape Tablemodel with Push Buttons.
Dimensions (WHD) 710 x 440 x 317 mm / 28 x 17.3 x 12.5 inch

"Bi-Ampli"-System mit EL84 für Hochton und 2x PL81 für Tiefton (700 Ohm).

Motorumschaltung der Wellenbereiche (Soft-touch).

FM abstimmung umschaltbar mit und ohne Stummschaltung.

Ortsendertaste für einen Sender im MW-Bereich.

Chassis wie FX995A und FX997A.

Bandswitches for all AM bands and FM with motor control and illuminated push-button selectors.

AM radio with 2 built-in ferroceptors in Faraday cage. The 2 ferroceptors are connected in series for LW and in parallel for BC.

  • LW: 150 - 345 kHz.
  • BC: 517 - 1620 kHz.
  • BC "Local": 517 - 1615 kHz (with its own tuning capacitor and scale).
  • SW1: 1,6 - 5,2 MHz (185m - 57,5m).
  • SW2: 5,1 - 15 MHz (59m - 20m) with fine tuning (S43) on separate scale.
  • SW3: 14,7 - 26,5 MHz (20,4m - 11,3m) with fine tuning (S43) on separate scale.

AM I.F. filters with variable bandwidth, mechanically coupled to the treble tone control.

FM radio with dipole antenna input: 87.5 - 100 MHz with or without silent tuning.
Separated tone control for bass and treble.
Amplifier: "Bi-Ampli" separated output stages for bass and treble. 
The bass amplifier is of SRPP* type which act as a push-pull amplifier (2x PL81).
The treble amplifier is of common single ended design (EL84).
  • 9758A (24 cm, 700Ω) for bass.
  • 9768M (15 cm, 5Ω, co-axial) for treble.
Dial lamps:
  • 7x 8089N (bajonet, 12V/100mA).
  • 5x 7994N (bajonet, 7,2V/100mA).
  • 3x 8024N (bajonet, 6,3V/300mA).
This radio uses the same chassis as models FX995A and FX997A.
*Shunt Regulated Push Pull.
Net weight (2.2 lb = 1 kg) 27 kg / 59 lb 7.5 oz (59.471 lb)
Price in first year of sale 820.00 hfl
Collectors' prices  
Literature/Schematics (1) -- Original-techn. papers.

All listed radios etc. from Philips; Eindhoven (tubes international!); Miniwatt
Here you find 4859 models, 4067 with images and 3245 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.


Forum contributions about this model
Philips; Eindhoven: Bi-Ampli BX998A
Threads: 7 | Posts: 22
Hits: 2014     Replies: 3
philips: BX998A; Bi-Ampli
Maurice Karasz


Le fusible Z1 de ma radio une Philips BX998A a grillé. C'est un fusible un peu bizarre, je n'arrive pas à touver d'info sur ce fusible ni sa valeur. Par quel type de fusible pourrais-je le remplacer ?

Merci pour l'aide qui pourra m'être apportée.





Wolfgang Bauer

Ceci est une copie de sauvegarde de métal de Wood.
Point de fusion d'environ 60 degrés, en fonction de l'alliage.
Cordialement WB.

Maurice Karasz


Possible to fix it or to replace by new one ?

Do you knoxw where I can find one equivalent




Wolfgang Bauer

You can solder the old fuse.
But it is the loss of this protection, since the melting point of solder is much higher then the wood's alloy.
A new fuse will be hard to get.
Regards WB.
Hits: 2227     Replies: 2
philips: BX998A; Bi-Ampli 27MHz alignement difficulty.
Paul E. Pinyot † 2013

I am aligning the AM bands and have difficulty at 27 MHz (11.1m) alignment point.  The 14.6MHZ alignment point adjusts in easily.  The 27 MHz (oscillator 27.452) is unobtainable.

My first question is where the Band Spread control is to be set.  Where do the instructions indicate where the Band Spread should be set?  There is a dart or pointer in the middle of the scale.  This does not work.  The minimum setting by the scale numbers does not work.  The oscillator will not reach 27.452 MHz.  I can receive WWV (20MHz, 15m) at oscillator 19.548 MHz.  

I hope my difficulty is with the Dutch to English translation and not circuit component related.  I am beginning to suspect some series capacitor being defective.  C50, C34 etc. I can minimize C40 the 27 MHz oscillator adjustment and not obtain the proper oscillator frequency.

Can any one give me any ideas to try before I start changing mica capacitors?

Thanks to all the fine experts here on the board.


I found the problem at 27MHz.  It was capacitor C50 210pf.  It measured good in the capacitor tester.  But I replaced it any how with the closest I had 220pf.  Now the band aligns in properly.


Henk van 't Kruis

Hello Paul, I send you the pre realease off my translayion into English by mail.


Gr. Henk van 't Kruis

Paul E. Pinyot † 2013

I will keep my eyes open for your letter.

Thank you,


Hits: 2372     Replies: 3
philips: BX998A; Bi-Ampli
Henk van 't Kruis

On request I started with the translation of the BX998A from Dutch into English. within 2 weeks the document is ready for the users here.

Also I just have revised a BX998A and is works like it was, just from the factory. I will store here the restoration story also.

gr. Henk



Paul E. Pinyot † 2013

gr. Henk

Have you comlleted the translation of the alignment instructions?  I am starting the alignment today. 

First I am replacing all the bad or carboned lamps.  Wow, it is not simple.  There are different voltage lamps.  Some appear to be in series.  soback to the shemativcs for now.



Update:  I managed to complete the IF and AM band alignments last night found on page 8.  It was relatively easy to deduce the Band, Frequency adjustment points and the intended adjustment.  I need to complete alignments from page 9 and beyond. 

One difficulty is not knowing where to set the band width.  So I set it in the middle at the "dart" or diamond point in the middle of the scale.

My translation has both Bass and Treble set to minimum for the 452 khz IF alignment.

Today I will try and translate pages 9 and perform the alignments.


Thomas Engelhardt

Hello Henk,

I have recently purchased a Bi-Ampli 998A and noticed the related documents on this site are all in Dutch. Since I saw your post from about 4 years ago on translation into English, I kindly would like to ask if you could provide me with a copy? 

In advance thanks for your help!




Henk van 't Kruis

Hello Thomas,

Tomorrow, I will place the article on RMORG.

Hits: 2048     Replies: 4
philips: Documents
Paul E. Pinyot † 2013

What alignment document or instructions should I use?

Suggestions welcome.




This model page is missing the text procedure on how to align this chassis.

I found the full alignment procedure on this page. This model has all the instructions for the BX998 chassis listed under the FX995a model radio.  


Robert Sarbell

Hello Paul,

Use the ".....abgl1" and "...abgl2" documents for Alignment instructions within the All Schematics section listing of the 19 items listed under Administration.


Paul E. Pinyot † 2013


Thank you for your reply.  I do have those two pages.  In fact I have all 9 pages downloaded.  And I still did not see the written alignment procedure.  I did however find a procedure on this site. 

By the way - You kindly taught me something new about RM.  I did not know all the schematics can be seen in a list view!  I will be using that tool. 

I would be happy to upload it but I do not want to violate any copyright laws. 

Now all I have to do is type all the German words into a translator to figure out what to do.  

There appears to be about 13 pages of text I think explaining the theory of operation and alignment.

Sheesh!  That will take some time.  But I want to do the job correctly.  So I have to do the work!  Then I can upload my work.

Thanks again,


Robert Sarbell


Welcome to the club - I have been typing from either German or the Dutch language for quite some time. . . the first was when I typed in 8 or 9 pages (I began in 2004) of data to understand the Grundig 5040W3D. And then I even had help from the esteemed engineer Herr Hans Knoll. That was the Grundig 4040/5040/5050 Technische daten TI 2/54 . . . .I could never have understood the re-stringing procedures without the help from  Hans Knoll.

The complete PHILIPS Service documente (all 27 pages in the Dutch language) is also downloadable from the NL Oude radio forum. Again, you can type in thetext and then translate or take the material to an Office Max or Office Depot; and perhaps they will have the OCR software which will directly convert the document into "text" for translation.

The alignment table for the BX998A, however, is shown clearly beginning on page 8. 

Good luck in whichever method you use. Just having a model BX998A is worth all of that effort!



Paul E. Pinyot † 2013


I like that OCR idea!


Hits: 1672     Replies: 1
philips: BX998A; Bi-Ampli
Ottmar Lauth


kann jemand, bitte, erläutern , wie  genau die Stummschaltung funktioniert ?

Vielen Dank im voraus und freundliche Grüße.

Ottmar Lauth

Ottmar Lauth


nachdem zwar mehr als hundert Leute meine Frage  gelesen, aber niemand darauf geantwortet hat, stelle ich hiermit meine eigene Theorie zur Diskusssion. Über Bestätigungen, Korrekturen oder Ergänzungen würde ich mich freuen.

Es gibt neben der weißen EIn/ Aus  - Taste noch 9 schwarze Programmtasten ( LW, MW, KW 1,KW 2, KW 3, Ortssender, Phono, "UKW empfindlich" und "UKW beste Qualität"). Wenn man eine dieser Tasten betätigt, wird der  Elektromotor in Gang gesetzt. Gespeist wird er durch eine Wechselspannung von 21,5 V. Ein Teil dieser Spannung gelangt an die Kathode der Diode X 1. Somit steht an deren Anode eine pulsierende negative Gleichspannung an. Diese wird durch das Siebglied R 68 und C 121 geglättet und gelangt an die Steuergitter der Röhrensysteme B 9 und B 10, die somit vorübergehend gesperrt werden. ( Vermutlich wird gleichzeitig auch die ECH 81 blockiert, aber das ist aus dem Schaltplan nur schwer auszumachen.) Diese Sperrung dauert zumindest so lange, wie der Motor unter Strom steht.

Mehrere Dinge sind mir allerdings noch unklar:

Was ist das für ein Bauteil, das mit Z 2 bezeichnet ist ?

Wodurch wird die Stromzufuhr wieder abgestellt, wenn der Motor den Wellenschalter an die von der Taste "gewünschte" Position gebracht hat ?

Hits: 8524     Replies: 2
philips: BX998A; Bi-Ampli
Leo Van Houten † 2013
  1 Philips BX998A  Export model. Writing on the scale has Enlish writing.  FM goes from 88-108 mcs. Interior is painted white.


Wolfgang Bauer

Hallo Mr. Van Houten,

please make a picture from the type plate.

Best regards WB.

Hans M. Knoll

Hello friends.

The white Paint with which the Case was coated inside, is a fire-hampering varnish, that so around 1960 in Canada as regulation FIRE PROTECTION.


regards Hans

Hits: 2625     Replies: 0
philips: BX998A;
Wouter Nieuwlaat † 27.5.18

neupreis war im 1956:  fl 820,-

ausgangsleistung Hochton= 4 Watt RMS,

ausgangsleistung Tiefton= 10 Watt RMS (!)

Hochton ausgangstransformator ist oft defektiv.

Philips; Eindhoven: Bi-Ampli BX998A
End of forum contributions about this model