Thursday, November 25, 2010

Corrections on Corrections

Another reader has pointed out mistakes. Thanks Tor.

In the entry below referring to Missing Capacitors C108 & C25, the text is correct but the drawing is wrong. C25 is shown on pin 3 of V9, it should be pin 3 of V8.

In the entry referring to C23, C24 and C7, R65 (10k) should be connected to pin 5 NOT pin 4 of V9.

I am rebuilding another R1155 using the book and I hope this process will eliminate the final problems.

Thursday, June 17, 2010

Another minor correction

Again a reader spots a small problem. Thanks to Chris for pointing this one out. The wiring schedule for S4 on p96 doesn't quite match the drawing below. The drawing is right regarding the destination of wires from tags 3 and 4 of S4 (Het On). The schedule has them swapped. Below is the corrected schedule.

Monday, April 5, 2010

R1155 Restoration Guide - Second Edition

The R1155 Receiver Restoration Guide is now available in a second edition, with the errors listed below corrected in the text and diagrams.

The price remains the same, £20.00 plus airmail post and packing from Australia.

Note: if you have a R1155L or N model, the Guide will help, but in these models there are differences in the coil box wiring because of the different frequency ranges, so you will need to work out your own coil box wiring. The rest of the circuitry is the same. If anyone wants to give me an L or N, I will do the necessary work and add some extra pages!

If you are uncertain whether the guide will be of value to you, check Ian's blog: for a users viewpoint.

Order from:
pnholtham at optusnet dot com dot au

by turning the above into a normal email address. I accept payment by PayPal to this address.

L3 tag positions

L3 in the coil box is the only coil with 6 tags. As shown on pages 64-68, the alignment of the tags is about 30 degrees out with how they actually mounted. Probably because I just did a copy and paste from L2 and added two more tags.

The diagram below shows the tag numbering that corresponds more closely with the physical arrangement. There is no problem with any of the wiring diagrams, it just might be easier to locate each pin on the modified diagram.

Missing capacitors, C108 & C25 and misplaced wire

Some more errors found by Ian ( while restoring his AD8882B. Two capacitors were missed in Section 4.4, the wiring around V5, V6, V8 & V9.

C25 goes between pin 3 of V8 and chassis. C108, is wired between the junction of R68/L25 (see the diagram on p98 for their location) and chassis. Normally this capacitor is soldered halfway along the wire between R68 and L25 pin 2 however it can just as easily be soldered directly to L25 pin 2.

The diagram on p110 should be amended as shown below.

Note that C108 normally goes over the top of the base of V8, not around the side as shown.

While we are in this area, on p111 the HT wire to V6 pin is shown in the diagram coming from tag 2 of the 9-way tag board. That is wrong, it should come from tag 3. Please amend your diagram.

Sunday, April 4, 2010

C23, C24 and C7

Something else that was left out of the wiring and pointed out by Ian. These three capacitors mount on the gear-end end wall of the coil box.

On p110 in the figure, delete the wiring shown to C23, C24 (that is R65) and C7.

On p134, 1st line below the figure. After the first sentence, add the following text:

There is one final task remaining. On p125 we left C7, C23 and C24 to be wired. These are the capacitors on the gear-end end wall of the coil box.

Tape C23 and C24 together noting the 6BA spacer washers between the two capacitors, then solder a yellow wire to the bottom tag on each capacitor. These two wires should be long enough to reach to the bias tag board.

Fit or replace R66 (10K) hidden in the lead to V9 top cap and poke it through the appropriate grommet in the chassis, then solder it to the lower tag of C23, the capacitor closest to the coil-box.

Now attach the capacitors to the side wall of the coil-box, being careful NOT to dislodge the 6BA spacer washers. Revise the dismantling procedure on p 10 to see how they came off.

R65 (10K) from V9 pin 4 can now be soldered to the lower tag on C24. Finally, using the two yellow wires, connect C23 to tag-board pin 8 and C24 to pin 9. C7 should be connected to the upper (joined) tags of C23 and C24. This point is then jointly wired to the earth-tag on the upper screw fixing the shaft support bracket adjacent to the gears and also to the triplet earth-tag on V9 base.

The diagram below shows the wiring to be added.

Resistance Checks p139

There are some errors with the tables of resistance checks starting on p139.

For the RF amp coils, all resistances should be from FSxf1 to FSxr1 and not from V3 grid (TC) to C40.

But check from V3 top cap to FSxr1, you should see 150k ohms, due to R71.

For the Loop aerial, delete the two lines referring to plug 3.

For the Osc. anode coils tap check (p140), on all five lines replace C35 with FSzf12

For the Osc. grid coils, delete three occurrences of C34 to C7x, replace with ditto mark.

Another DF wiring error - L24

Ian pointed out another wiring error preventing the DF side working correctly. I missed out a wire from the centre tap of L24 to the V1 V2 tag board. The lower diagram on p136 should be as shown below.

Below the last diagram on p137, before the two lines of text, add:

While in this area you can add R62 & R63 if you like. These are 2.2k static leak resistors from pins 1 and 2 of plug 1 earthed to the triplet on C93. I did not bother.

Wiring Errors around V1 & V2

In Section 4.10, p135, there are some vital wires missing in the diagrams. Firstly, add the following text to the end of the first paragraph:

Before fitting C93, refit C56 to the front panel (removed on page 21). One side of C56 is fitted with a resistor R57 grounded to MSb7f&r. The two V1 & V2 grid top caps should also now be wired here. The other side of C56 goes to MSb4.

This refers to preset trimmer C56, which is adjusted by a screwdriver through a front panel hole on set up. In the original text, this trimmer, resistor R57 and the two wires for the grid top caps of V1 & V2 were completely forgotten.

Amend the Master Switch wiring schedule on p120, for wafer b front, tag 7 to:

b7 rear and ground & R57

Also on p135, there is an error in the lower diagram, the cathodes of V1 & V2 were not linked. See below for the amended diagram.

Grounding wire on top of L4, L5, L6

On p125, Section 4.9.2, add this additional paragraph below the existing text:

Remember also now to link up the earths on the tops of the coil screening cans, and run the link across to the earth triplet on the screen plate between wafers d and e of the Master Switch.

Master Switch Wafer 'c' duplicate wire deletion

On page 123, top diagram, wafer 'c' front, the wire shown from tag 11 to grommet 6 should be deleted. It is duplicated by a wire from wafer 'c' rear tag 5. The correct drawing is shown below.

Notes on the diagram above:

1. There is no MScf5 tag, so there is no link between the front and rear tags as implied by the shaded tag on the diagram.

2. The wire from Tag 7 goes to the junction of R9, R68 and C103 near the bias tag board and not bias tag board tag 10. Amend the master swich wiring schedule on p120 to reflect the correction.

On page 127, line 10, in the list of odd wires, L3 p4 should read L3 p3

Note that this tag on the coil is also earthed to the triplet tag on L5. So add another line:

L3 pin 3 to triplet ground tag on L5, as shown in the diagram opposite on p126

Ian's AD8882B blog

Have a look at Ian's AD8882B restoration blog. The AD8882B is the civilian version of the R1155 installed in a number of BOAC aircraft immediately after the war.

Ian used the R1155 Restoration book to completely rebuilt his receiver in just 25 days! He found a number of wiring and typographical errors which I will now be correcting and publishing here.

See below for the typos, and above for the wiring errors he found.

The great thing about Ian using the book to guide the restoration of his receiver is that it gave the book a through work out. His receiver is fully functional now on all ranges, and the DF side also works correctly. He tells me he used it to copy (in Scotland) a VK7 station on 40m ssb. All you need to do to resolve ssb is choose your sideband (by adjusting the BFO to the correct side of the IF passband), turn off the AVC (put the Master switch to the Omni position), and away you go. Here is his web site:

List of Typos corrected in the 2nd Edition

Here are some typographical errors pointed out by readers. You might like to amend your copy.

p7 third bullet: ....a drop or two of WD40 to every fastener.....

p7 last bullet: ....A set of Allen...

p26 2nd paragraph: ....the 'pencil scale' shown below will come.....

p32 1st paragraph: ....4µF and showed no signs of leakage.

p35 3rd paragraph: ....capacitor (L21 only), .... [remove space before comma]

p48 lower diagram, top shaded resistor is R46, the scan may make it appear to be R45

p50 lower diagram: C12 is actually 0.1µF not 0.01µF as shown

p55 in the list of potentiometers, R23 is the Meter Amplitude control, not Balance

p97 2nd paragraph: ....seems to work reasonably well.

p99 2nd paragraph, last sentence: delete the words the screw

p118 last paragraph: the two references to S2 should both be S3

p119 wiring schedules, three references to S2 should all be S3

p136 last paragraph: described in Section 4.12, leave....

p140 1st paragraph: ....different, just pro-rata the values...

p144 2nd paragraph: ....Jones socket pin and then clipped....

p144 3 paragraph: ....Then as before,....

Tuesday, February 9, 2010


A new printing of the R1155 restoration guide is now available. Just a few minor typographical errors cleaned up.

Plenty of copies in stock, order yours from:

p.holtham at uqconnect dot net

The price remains the same despite the fall in the value of the aussie dollar against most other currencies. A$45.00 or £20.00 plus postage and packing. For other currencies and post and packing costs, email me.