The PK-4 SSR keyer kit - 10/05/2005
March 28, 2023: SSR option is now $7 due to parts price increases
January 2019: kit now includes a solder masked, silk screened circuit board
July 7, 2023 see the Keyer Enclosure Kit to house the keyer kit
05/21/2020: put a PK-4 demo video on Youtube .
12/23/2013: see the new SMT Keyer kit, PK-4 version
The PK-4 SSR is the latest in the PK series of keyer kits.
It replaces the popular PK-4 kit but
adds an optional Solid State Relay (SSR) 6 pin chip for
tube keying, similar to the Keyer Accessory kit .
The Solid State Relay is rated at +/- 120 mA and +/- 400 V. Some
cathode keyed rigs such as the Knight T-150
may require the Keyall
due to larger than 120 mA currents. If in
doubt, measure the current and voltage with
The PK-4 is fully pin compatible
with the Norcal keyer.
The PK-4 is pin compatible
with the PK-3, PK-2 and PK-Basic (Tick and K8 chips, too) with the addition of a 10k ohm pullup resistor
between pin 1 and 4 of the keyer chip socket. The PK-4 shares the pot speed
control of the previous PK series and the Norcal keyer but it has a large number of new additional
features. Here are a few highlights:
pot or paddle speed control, 5 to 50 WPM
two 80 character memories plus an 80 character callsign memory
OR optionally two 80 and two 40 character memories
memories & settings retained without power (EEPROM)
Ultimatic or Iambic A or B keying modes
beacon mode, variable delay, up to 60 seconds
adjustable element weighting
variable sidetone frequency
low standby power (about 7 ua at 5 V, with regulator)
small size (1 by 1.5 inches)
Kit price (no doc) is $18.00 + shipping/handling
Kit with optional SSR: price (no doc) is $25.00 + shipping/handling
PK-4 chip (no doc) is $5.00 + shipping/handling
(multiple purchases of the PK-4 chip (no doc), will be
sent in a single anti-static bag)
Printed manuals available for an additional charge or
save money by downloading and printing your own copy of the
hookup diagram .
Don't get sub menus ?? See the
sub menu doc
Print out a Kit
order form to figure your order manually
to let your browser do the math!
For larger quantity purchases, manual pricing or to combine with other items, just send an email to:
with your question.
Downloadable files for the PK-4 SSR
The Acrobat files of complex diagrams (like the PK-4 schematic) may not
view well on your computer screen - suggestion: use the magnifier to zoom in
for better detail or print out the file.
pk4ssr2.pdf (58k) - PK-4 SSR schematic
pk4ssrh.pdf (54k) - PK-4 SSR manual in Acrobat format
pk4hu2.pdf (32k) - PK-4 SSR Hookup diagram in Acrobat format
pk4ssrl.jpg (69k) - PK-4 SSR larger picture
pk4diag.txt (1k) - quick PK-4 resistance / voltage checks text file
pk4ts.htm (1k) - PK-4 Troubleshooting guide
pk4menus.pdf (11k) - a PK-4 menu "cheat sheet" by Chuck Carpenter, W5USJ (thanks, Chuck)
stalkin.pdf (16k) - Stalking the Wild Multipress! - an Acrobat file
of a hardware method to solve the problem of pressing 2 or 3 switches at the same time.
modeab.pdf (8k) - an Acrobat file explaning the differences between Iambic mode A and B
ultimat.txt (4k) - a text file on the Ultimatic mode