diff --git a/src/mame/sinclair/glukrs.cpp b/src/mame/sinclair/glukrs.cpp
index becb944c2fd56..383653f72aab4 100644
--- a/src/mame/sinclair/glukrs.cpp
+++ b/src/mame/sinclair/glukrs.cpp
@@ -14,12 +14,20 @@
 #include "glukrs.h"
 
 glukrs_device::glukrs_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
-		: mc146818_device(mconfig, GLUKRS, tag, owner, 32'768)
+		: mc146818_device(mconfig, GLUKRS, tag, owner, clock)
 {
 	m_tuc = 1984;
 	set_24hrs(true);
 }
 
+void glukrs_device::device_validity_check(validity_checker &valid) const
+{
+	mc146818_device::device_validity_check(valid);
+
+	if (clock() != 32'768)
+		osd_printf_error("Clock %u is different from expected 32'768\n", clock());
+}
+
 void glukrs_device::device_start()
 {
 	mc146818_device::device_start();
diff --git a/src/mame/sinclair/glukrs.h b/src/mame/sinclair/glukrs.h
index f984c245e2d00..4fcc7ee0949c4 100644
--- a/src/mame/sinclair/glukrs.h
+++ b/src/mame/sinclair/glukrs.h
@@ -12,7 +12,7 @@
 class glukrs_device : public mc146818_device
 {
 public:
-	glukrs_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock = 0);
+	glukrs_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock = 32'768);
 
 	void enable() { m_glukrs_active = true; }
 	void disable() { m_glukrs_active = false; }
@@ -24,6 +24,7 @@ class glukrs_device : public mc146818_device
 	virtual void data_w(u8 data) override { if (m_glukrs_active) { mc146818_device::data_w(data); } }
 
 protected:
+	virtual void device_validity_check(validity_checker &valid) const override;
 	void device_start() override ATTR_COLD;
 	void device_reset() override ATTR_COLD;
 
diff --git a/src/mame/sinclair/pentevo.cpp b/src/mame/sinclair/pentevo.cpp
index f7d71bd75e5b9..6bd5a4ef994c6 100644
--- a/src/mame/sinclair/pentevo.cpp
+++ b/src/mame/sinclair/pentevo.cpp
@@ -728,7 +728,7 @@ void pentevo_state::pentevo(machine_config &config)
 	m_ram->set_default_size("4M");
 	RAM(config, m_char_ram).set_default_size("2048").set_default_value(0);
 
-	GLUKRS(config, m_glukrs);
+	GLUKRS(config, m_glukrs, 32.768_kHz_XTAL);
 	SPI_SDCARD(config, m_sdcard, 0);
 	m_sdcard->set_prefer_sdhc();
 	m_sdcard->spi_miso_callback().set(FUNC(pentevo_state::spi_miso_w));
diff --git a/src/mame/sinclair/tsconf.cpp b/src/mame/sinclair/tsconf.cpp
index b2e14797714b3..d78c0d33372d7 100644
--- a/src/mame/sinclair/tsconf.cpp
+++ b/src/mame/sinclair/tsconf.cpp
@@ -296,7 +296,7 @@ void tsconf_state::tsconf(machine_config &config)
 
 	m_ram->set_default_size("4096K").set_default_value(0x00); // must be random but 0x00 behaves better than 0xff in tested software
 
-	GLUKRS(config, m_glukrs);
+	GLUKRS(config, m_glukrs, 32.768_kHz_XTAL);
 
 	TSCONF_DMA(config, m_dma, 28_MHz_XTAL);
 	m_dma->in_mreq_callback().set(FUNC(tsconf_state::ram_read16));